
11  structures 951  species 1  interaction 4642  sequences 92  architectures

Family: Linker_histone (PF00538)

Summary: linker histone H1 and H5 family



Histone Edit Wikipedia article


In biology, histones are highly alkaline proteins found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes.[1][2] They are the chief protein components of chromatin, acting as spools around which DNA winds, and playing a role in gene regulation. Without histones, the unwound DNA in chromosomes would be very long (a length to width ratio of more than 10 million to 1 in human DNA). For example, each human diploid cell (containing 23 pairs of chromosomes) has about 1.8 meters of DNA; wound on the histones, the diploid cell has about 90 micrometers (0.09 mm) of chromatin. When the diploid cells are duplicated and condensed during mitosis, the result is about 120 micrometers of chromosomes.[3]

Core histone H2A/H2B/H3/H4
Protein H2AFJ PDB 1aoi.png
Symbol Histone
Pfam PF00125
Pfam clan CL0012
InterPro IPR007125
SCOP 1hio
linker histone H1 and H5 family
PBB Protein HIST1H1B image.jpg
PDB rendering of HIST1H1B based on 1ghc.
Symbol Linker_histone
Pfam PF00538
InterPro IPR005818
SCOP 1hst

Classes and histone variants

Five major families of histones exist: H1/H5, H2A, H2B, H3, and H4.[2][4][5][6] Histones H2A, H2B, H3 and H4 are known as the core histones, while histones H1/H5 are known as the linker histones.

The core histones all exist as dimers, which are similar in that they all possess the histone fold domain: three alpha helices linked by two loops. It is this helical structure that allows for interaction between distinct dimers, particularly in a head-tail fashion (also called the handshake motif).[7] The resulting four distinct dimers then come together to form one octameric nucleosome core, approximately 63 Angstroms in diameter (a solenoid (DNA)-like particle). Around 146 base pairs (bp) of DNA wrap around this core particle 1.65 times in a left-handed super-helical turn to give a particle of around 100 Angstroms across.[8] The linker histone H1 binds the nucleosome at the entry and exit sites of the DNA, thus locking the DNA into place[9] and allowing the formation of higher order structure. The most basic such formation is the 10 nm fiber or beads on a string conformation. This involves the wrapping of DNA around nucleosomes with approximately 50 base pairs of DNA separating each pair of nucleosomes (also referred to as linker DNA). Higher-order structures include the 30 nm fiber (forming an irregular zigzag) and 100 nm fiber, these being the structures found in normal cells. During mitosis and meiosis, the condensed chromosomes are assembled through interactions between nucleosomes and other regulatory proteins.

Histones are subdivided into canonical replication-dependent histones that are expressed during the S-phase of cell cycle and replication-independent histone variants, expressed during the whole cell cycle. In animals, genes encoding canonical histones are typically clustered along the chromosome, lack introns and use a stem loop structure at the 3’ end instead of a polyA tail. Genes encoding histone variants are usually not clustered, have introns and their mRNAs are regulated with polyA tails. Complex multicellular organisms typically have a higher number of histone variants providing a variety of different functions. Recent data are accumulating about the roles of diverse histone variants highlighting the functional links between variants and the delicate regulation of organism development. Histone variants from different organisms, their classification and variant specific features can be found in "HistoneDB 2.0 - Variants" database.

The following is a list of human histone proteins:

Super family Family Subfamily Members
Linker H1 H1F H1F0, H1FNT, H1FOO, H1FX


The nucleosome core is formed of two H2A-H2B dimers and a H3-H4 tetramer, forming two nearly symmetrical halves by tertiary structure (C2 symmetry; one macromolecule is the mirror image of the other).[8] The H2A-H2B dimers and H3-H4 tetramer also show pseudodyad symmetry. The 4 'core' histones (H2A, H2B, H3 and H4) are relatively similar in structure and are highly conserved through evolution, all featuring a 'helix turn helix turn helix' motif (DNA-binding protein motif that recognize specific DNA sequence). They also share the feature of long 'tails' on one end of the amino acid structure - this being the location of post-translational modification (see below).



In all, histones make five types of interactions with DNA:

  • Nonpolar interactions between the histone and deoxyribose sugars on DNA


Histones are subject to post translational modification by enzymes primarily on their N-terminal tails, but also in their globular domains.[12][13] Such modifications include methylation, citrullination, acetylation, phosphorylation, SUMOylation, ubiquitination, and ADP-ribosylation. This affects their function of gene regulation.

In general, genes that are active have less bound histone, while inactive genes are highly associated with histones during interphase[14]. It also appears that the structure of histones has been evolutionarily conserved, as any deleterious mutations would be severely maladaptive. All histones have a highly positively charged N-terminus with many lysine and arginine residues.


Histones were discovered in 1884 by Albrecht Kossel. The word "histone" dates from the late 19th century and is from the German word "Histon", a word itself of uncertain origin - perhaps from the Greek histanai or histos. Until the early 1990s, histones were dismissed by most as inert packing material for eukaryotic nuclear DNA, a view based in part on the models of Mark Ptashne and others, who believed that transcription was activated by protein-DNA and protein-protein interactions on largely naked DNA templates, as is the case in bacteria.

During the 1980s, Yahli Lorch and Roger Kornberg[15] showed that a nucleosome on a core promoter prevents the initiation of transcription in vitro, and Michael Grunstein[16] demonstrated that histones repress transcription in vivo, leading to the idea of the nucleosome as a general gene repressor. Relief from repression is believed to involve both histone modification and the action of chromatin-remodeling complexes. Vincent Allfrey and Alfred Mirsky earlier proposed a role of histone modification in transcriptional activation,[17] regarded as a molecular manifestation of epigenetics. Michael Grunstein[18] and David Allis[19] found support for this proposal, in the importance of histone acetylation for transcription in yeast and the activity of the transcriptional activator Gcn5 as a histone acetyltransferase.

The discovery of the H5 histone appears to date back to the 1970s,[20] and it is now considered an isoform of Histone H1.[2][4][5][6]

Conservation across species

Histones are found in the nuclei of eukaryotic cells, and in certain Archaea, namely Thermoproteales and Euryarchaea, but not in bacteria. The unicellular algae known as dinoflagellates were previously thought to be the only eukaryotes that completely lack histones,[21] however, later studies showed that their DNA still encodes histone genes.[22]



There are some variant forms in some of the major classes. They share amino acid sequence homology and core structural similarity to a specific class of major histones but also have their own feature that is distinct from the major histones. These minor histones usually carry out specific functions of the chromatin metabolism. For example, histone H3-like CENPA is associated with only the centromere region of the chromosome. Histone H2A variant H2A.Z is associated with the promoters of actively transcribed genes and also involved in the prevention of the spread of silent heterochromatin.[24] Furthermore, H2A.Z has roles in chromatin for genome stability.[25] Another H2A variant H2A.X is phosphorylated at S139 in regions around double-strand breaks and marks the region undergoing DNA repair.[26] Histone H3.3 is associated with the body of actively transcribed genes.[27]


Compacting DNA strands


Chromatin regulation

Histones undergo posttranslational modifications that alter their interaction with DNA and nuclear proteins. The H3 and H4 histones have long tails protruding from the nucleosome, which can be covalently modified at several places. Modifications of the tail include methylation, acetylation, phosphorylation, ubiquitination, SUMOylation, citrullination, and ADP-ribosylation. The core of the histones H2A and H2B can also be modified. Combinations of modifications are thought to constitute a code, the so-called "histone code".[28][29] Histone modifications act in diverse biological processes such as gene regulation, DNA repair, chromosome condensation (mitosis) and spermatogenesis (meiosis).[30]

The common nomenclature of histone modifications is:

  • The name of the histone (e.g., H3)


Examples of histone modifications in transcriptional regulation
Type of
H3K4 H3K9 H3K14 H3K27 H3K79 H3K36 H4K20 H2BK5 H2BK20
mono-methylation activation[31] activation[32] activation[32] activation[32][33] activation[32] activation[32]
di-methylation repression[34] repression[34] activation[33]
tri-methylation activation[35] repression[32] repression[32] activation,[33]
activation repression[34]
acetylation activation[35] activation[35] activation[36] activation

Functions of histone modifications



Chemistry of histone modifications

Lysine methylation

Methyl lysine.svg


Arginine methylation

Methyl arginine.svg


Arginine citrullination


Lysine acetylation

Acetyl lysine.tif


Serine/threonine/tyrosine phosphorylation

Amino acid phosphorylations.tif


Functions in transcription


Actively transcribed genes

Two histone modifications are particularly associated with active transcription:

Trimethylation of H3 lysine 4 (H3K4me3)
This trimethylation occurs at the promoter of active genes[39][40][41] and is performed by the COMPASS complex.[42][43][44] Despite the conservation of this complex and histone modification from yeast to mammals, it is not entirely clear what role this modification plays. However, it is an excellent mark of active promoters and the level of this histone modification at a gene’s promoter is broadly correlated with transcriptional activity of the gene. The formation of this mark is tied to transcription in a rather convoluted manner: early in transcription of a gene, RNA polymerase II undergoes a switch from initiating’ to ‘elongating’, marked by a change in the phosphorylation states of the RNA polymerase II C terminal domain (CTD). The same enzyme that phosphorylates the CTD also phosphorylates the Rad6 complex,[45][46] which in turn adds a ubiquitin mark to H2B K123 (K120 in mammals).[47] H2BK123Ub occurs throughout transcribed regions, but this mark is required for COMPASS to trimethylate H3K4 at promoters.[48][49]
Trimethylation of H3 lysine 36 (H3K36me3)
This trimethylation occurs in the body of active genes and is deposited by the methyltransferase Set2.[50] This protein associates with elongating RNA polymerase II, and H3K36Me3 is indicative of actively transcribed genes.[51] H3K36Me3 is recognised by the Rpd3 histone deacetylase complex, which removes acetyl modifications from surrounding histones, increasing chromatin compaction and repressing spurious transcription.[52][53][54] Increased chromatin compaction prevents transcription factors from accessing DNA, and reduces the likelihood of new transcription events being initiated within the body of the gene. This process therefore helps ensure that transcription is not interrupted.

Repressed genes

Three histone modifications are particularly associated with repressed genes:

Trimethylation of H3 lysine 27 (H3K27me3)
This histone modification is depositied by the polycomb complex PRC2.[55] It is a clear marker of gene repression,[56] and is likely bound by other proteins to exert a repressive function. Another polycomb complex, PRC1, can bind H3K27me3[56] and adds the histone modification H2AK119Ub which aids chromatin compaction.[57][58] Based on this data it appears that PRC1 is recruited through the action of PRC2, however, recent studies show that PRC1 is recruited to the same sites in the absence of PRC2.[59][60]
Di and tri-methylation of H3 lysine 9 (H3K9me2/3)
H3K9me2/3 is a well-characterised marker for heterochromatin, and is therefore strongly associated with gene repression. The formation of heterochromatin has been best studied in the yeast Schizosaccharomyces pombe, where it is initiated by recruitment of the RNA-induced transcriptional silencing (RITS) complex to double stranded RNAs produced from centromeric repeats.[61] RITS recruits the Clr4 histone methyltransferase which deposits H3K9me2/3.[62] This process is called histone methylation. H3K9Me2/3 serves as a binding site for the recruitment of Swi6 (heterochromatin protein 1 or HP1, another classic heterochromatin marker)[63][64] which in turn recruits further repressive activities including histone modifiers such as histone deacetylases and histone methyltransferases.
Trimethylation of H4 lysine 20 (H4K20me3)
This modification is tightly associated with heterochromatin,[65][66] although its functional importance remains unclear. This mark is placed by the Suv4-20h methyltransferase, which is at least in part recruited by heterochromatin protein 1.[65]

Bivalent promoters


Other functions

DNA damage


Phosphorylation of H2AX at serine 139 (γH2AX)
Phosphorylated H2AX (also known as gamma H2AX) is a marker for DNA double strand breaks,[68] and forms part of the response to DNA damage.[26][69] H2AX is phosphorylated early after detection of DNA double strand break, and forms a domain extending many kilobases either side of the damage.[68][70][71] Gamma H2AX acts as a binding site for the protein MDC1, which in turn recruits key DNA repair proteins[72] (this complex topic is well reviewed in[73]) and as such, gamma H2AX forms a vital part of the machinery that ensures genome stability.
Acetylation of H3 lysine 56 (H3K56Ac)
H3K56Acx is required for genome stability.[74][75] H3K56 is acetylated by the p300/Rtt109 complex,[76][77][78] but is rapidly deacetylated around sites of DNA damage. H3K56 acetylation is also required to stabilise stalled replication forks, preventing dangerous replication fork collapses.[79][80] Although in general mammals make far greater use of histone modifications than microorganisms, a major role of H3K56Ac in DNA replication exists only in fungi, and this has become a target for antibiotic development.[81]

DNA repair

Trimethylation of H3 lysine 36 (H3K36me3)

H3K36me3 has the ability to recruit the MSH2-MSH6 (hMutSα) complex of the DNA mismatch repair pathway.[82] Consistenty, regions of the human genome with high levels of H3K36me3 accumulate less somatic mutations due to mismatch repair activity.[83]

Chromosome condensation

Phosphorylation of H3 at serine 10 (phospho-H3S10)
The mitotic kinase aurora B phosphorylates histone H3 at serine 10, triggering a cascade of changes that mediate mitotic chromosome condensation.[84][85] Condensed chromosomes therefore stain very strongly for this mark, but H3S10 phosphorylation is also present at certain chromosome sites outside mitosis, for example in pericentric heterochromatin of cells during G2. H3S10 phosphorylation has also been linked to DNA damage caused by R loop formation at highly transcribed sites.[86]
Phosphorylation of H2B at serine 10 (yeast) or serine 14 (mammals) is also linked to chromatin condensation, but for the very different purpose of mediating chromosome condensation during apoptosis.[87][88] This mark is not simply a late acting bystander in apoptosis as yeast carrying mutations of this residue are resistant to hydrogen peroxide-induced apoptotic cell death.


Epigenetic modifications of histone tails in specific regions of the brain are of central importance in addictions.[89][90][91] Once particular epigenetic alterations occur, they appear to be long lasting "molecular scars" that may account for the persistence of addictions.[89]

Cigarette smokers (about 15% of the US population) are usually addicted to nicotine.[92] After 7 days of nicotine treatment of mice, acetylation of both histone H3 and histone H4 was increased at the FosB promoter in the nucleus accumbens of the brain, causing 61% increase in FosB expression.[93] This would also increase expression of the splice variant Delta FosB. In the nucleus accumbens of the brain, Delta FosB functions as a "sustained molecular switch" and "master control protein" in the development of an addiction.[94][95]

About 7% of the US population is addicted to alcohol. In rats exposed to alcohol for up to 5 days, there was an increase in histone 3 lysine 9 acetylation in the pronociceptin promoter in the brain amygdala complex. This acetylation is an activating mark for pronociceptin. The nociceptin/nociceptin opioid receptor system is involved in the reinforcing or conditioning effects of alcohol.[96]

Methamphetamine addiction occurs in about 0.2% of the US population.[97] Chronic methamphetamine use causes methylation of the lysine in position 4 of histone 3 located at the promoters of the c-fos and the C-C chemokine receptor 2 (ccr2) genes, activating those genes in the nucleus accumbens (NAc).[98] c-fos is well known to be important in addiction.[99] The ccr2 gene is also important in addiction, since mutational inactivation of this gene impairs addiction.[98]

Histone synthesis

The first step of chromatin structure duplication is the synthesis of histone proteins: H1, H2A, H2B, H3, H4. These proteins are synthesized during S phase of the cell cycle. There are different mechanisms which contribute to the increase of histone synthesis.


Yeast carry one or two copies of each histone gene, which are not clustered but rather scattered throughout chromosomes. Histone gene transcription is controlled by multiple gene regulatory proteins such as transcription factors which bind to histone promoter regions. In budding yeast, the candidate gene for activation of histone gene expression is SBF. SBF is a transcription factor that is activated in late G1 phase, when it dissociates from its repressor Whi5. This occurs when Whi5 is phosphorylated by Cdc8 which is a G1/S Cdk.[100] Suppression of histone gene expression outside of S phases is dependent on Hir proteins which form inactive chromatin structure at the locus of histone genes, causing transcriptional activators to be blocked.[101][102]


In metazoans the increase in the rate of histone synthesis is due to the increase in processing of pre-mRNA to its mature form as well as decrease in mRNA degradation; this results in an increase of active mRNA for translation of histone proteins. The mechanism for mRNA activation has been found to be the removal of a segment of the 3’ end of the mRNA strand, and is dependent on association with stem-loop binding protein (SLBP).[103] SLBP also stabilizes histone mRNAs during S phase by blocking degradation by the 3’hExo nuclease.[104] SLBP levels are controlled by cell-cycle proteins, causing SLBP to accumulate as cells enter S phase and degrade as cells leave S phase. SLBP are marked for degradation by phosphorylation at two threonine residues by cyclin dependent kinases, possibly cyclin A/ cdk2, at the end of S phase.[105] Metazoans also have multiple copies of histone genes clustered on chromosomes which are localized in structures called Cajal bodies as determined by genome-wide chromosome conformation capture analysis (4C-Seq).[106]

Link between cell-cycle control machinery and histone synthesis

Nuclear protein Ataxia-Telangiectasia (NPAT), also known as nuclear protein coactivator of histone transcription, is a transcription factor which activates histone gene transcription on chromosomes 1 and 6 of human cells. NPAT is also a substrate of cyclin E-Cdk2, which is required for the transition between G1 phase and S phase. NPAT activates histone gene expression only after it has been phosphorylated by the G1/S-Cdk cyclin E-Cdk2 in early S phase.[107] This shows an important regulatory link between cell-cycle control and histone synthesis.

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External links


This is the Wikipedia entry entitled "Histone H1". More...

Histone H1 Edit Wikipedia article

linker histone H1 and H5 family
PBB Protein HIST1H1B image.jpg
PDB rendering of HIST1H1B based on 1ghc.
Symbol Linker_histone
Pfam PF00538
InterPro IPR005818
SCOP 1hst

Histone H1 is one of the five main histone protein families which are components of chromatin in eukaryotic cells. Though highly conserved, it is nevertheless the most variable histone in sequence across species.


A diagram showing where H1 can be found in the nucleosome

Metazoan H1 proteins feature a central globular domain and long C- and short N-terminal tails. H1 is involved with the packing of the "beads on a string" sub-structures into a high order structure, whose details have not yet been solved.[1]


Unlike the other histones, H1 does not make up the nucleosome "bead". Instead, it sits on top of the structure, keeping in place the DNA that has wrapped around the nucleosome. H1 is present in half the amount of the other four histones, which contribute two molecules to each nucleosome bead. In addition to binding to the nucleosome, the H1 protein binds to the "linker DNA" (approximately 20-80 nucleotides in length) region between nucleosomes, helping stabilize the zig-zagged 30 nm chromatin fiber.[2] Much has been learned about histone H1 from studies on purified chromatin fibers. Ionic extraction of linker histones from native or reconstituted chromatin promotes its unfolding under hypotonic conditions from fibers of 30 nm width to beads-on-a-string nucleosome arrays.[3][4][5]

It is uncertain whether H1 promotes a solenoid-like chromatin fiber, in which exposed linker DNA is shortened, or whether it merely promotes a change in the angle of adjacent nucleosomes, without affecting linker length[6] However, linker histones have been demonstrated to drive the compaction of chromatin fibres that had been reconstituted in vitro using synthetic DNA arrays of the strong '601' nucleosome positioning element. [7] Nuclease digestion and DNA footprinting experiments suggest that the globular domain of histone H1 localizes near the nucleosome dyad, where it protects approximately 15-30 base pairs of additional DNA.[8][9][10][11] In addition, experiments on reconstituted chromatin reveal a characteristic stem motif at the dyad in the presence of H1.[12] Despite gaps in our understanding, a general model has emerged wherein H1’s globular domain closes the nucleosome by crosslinking incoming and outgoing DNA, while the tail binds to linker DNA and neutralizes its negative charge.[6][10]

Many experiments addressing H1 function have been performed on purified, processed chromatin under low-salt conditions, but H1’s role in vivo is less certain. Cellular studies have shown that overexpression of H1 can cause aberrant nuclear morphology and chromatin structure, and that H1 can serve as both a positive and negative regulator of transcription, depending on the gene.[13][14][15] In Xenopus egg extracts, linker histone depletion causes ~2-fold lengthwise extension of mitotic chromosomes, while overexpression causes chromosomes to hypercompact into an inseparable mass.[16][17] Complete knockout of H1 in vivo has not been achieved in multicellular organisms due to the existence of multiple isoforms that may be present in several gene clusters, but various linker histone isoforms have been depleted to varying degrees in Tetrahymena, C. elegans, Arabidopsis, fruit fly, and mouse, resulting in various organism-specific defects in nuclear morphology, chromatin structure, DNA methylation, and/or specific gene expression.[18][19][20]


While most histone H1 in the nucleus is bound to chromatin, H1 molecules shuttle between chromatin regions at a fairly high rate.[21][22]

It is difficult to understand how such a dynamic protein could be a structural component of chromatin, but it has been suggested that the steady-state equilibrium within the nucleus still strongly favors association between H1 and chromatin, meaning that despite its dynamics, the vast majority of H1 at any given timepoint is chromatin bound.[23] H1 compacts and stabilizes DNA under force and during chromatin assembly, which suggests that dynamic binding of H1 may provide protection for DNA in situations where nucleosomes need to be removed.[24]

Cytoplasmic factors appear to be necessary for the dynamic exchange of histone H1 on chromatin, but these have yet to be specifically identified.[25] H1 dynamics may be mediated to some degree by O-glycosylation and phosphorylation. O-glycosylation of H1 may promote chromatin condensation and compaction. Phosphorylation during interphase has been shown to decrease H1 affinity for chromatin and may promote chromatin decondensation and active transcription. However, during mitosis phosphorylation has been shown to increase the affinity of H1 for chromosomes and therefore promote mitotic chromosome condensation.[17]


The H1 family in animals includes multiple H1 isoforms that can be expressed in different or overlapping tissues and developmental stages within a single organism. The reason for these multiple isoforms remains unclear, but both their evolutionary conservation from sea urchin to humans as well as significant differences in their amino acid sequences suggest that they are not functionally equivalent.[26][27][28] One isoform is histone H5, which is only found in avian erythrocytes, which are unlike mammalian erythrocytes in that they have nuclei. Another isoform is the oocyte/zygotic H1M isoform (also known as B4 or H1foo), found in sea urchins, frogs, mice, and humans, which is replaced in the embryo by somatic isoforms H1A-E, and H10 which resembles H5.[28][29][30][31] Despite having more negative charges than somatic isoforms, H1M binds with higher affinity to mitotic chromosomes in Xenopus egg extracts.[17]

Post-translational Modifications

Like other histones, the histone H1 family is extensively post-translationally modified (PTMs). This includes serine and threonine phosphorylation, lysine acetylation, lysine methylation and ubiquitination. [32] These PTMs serve a variety of functions but are less well studied than the PTMs of other histones.

See also


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  13. ^ Dworkin-Rastl E, Kandolf H, Smith RC (February 1994). "The maternal histone H1 variant, H1M (B4 protein), is the predominant H1 histone in Xenopus pregastrula embryos". Dev. Biol. 161 (2): 425–39. doi:10.1006/dbio.1994.1042. PMID 8313993. 
  14. ^ Brown DT, Alexander BT, Sittman DB (February 1996). "Differential effect of H1 variant overexpression on cell cycle progression and gene expression". Nucleic Acids Res. 24 (3): 486–93. doi:10.1093/nar/24.3.486. PMC 145659Freely accessible. PMID 8602362. 
  15. ^ Gunjan A, Alexander BT, Sittman DB, Brown DT (December 1999). "Effects of H1 histone variant overexpression on chromatin structure". J. Biol. Chem. 274 (53): 37950–6. doi:10.1074/jbc.274.53.37950. PMID 10608862. 
  16. ^ Maresca TJ, Freedman BS, Heald R (June 2005). "Histone H1 is essential for mitotic chromosome architecture and segregation in Xenopus laevis egg extracts". J. Cell Biol. 169 (6): 859–69. doi:10.1083/jcb.200503031. PMC 2171634Freely accessible. PMID 15967810. 
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linker histone H1 and H5 family Provide feedback

Linker histone H1 is an essential component of chromatin structure. H1 links nucleosomes into higher order structures Histone H1 is replaced by histone H5 in some cell types.

Literature references

  1. Ramakrishnan V, Finch JT, Graziano V, Lee PL, Sweet RM; , Nature 1993;362:219-223.: Crystal structure of globular domain of histone H5 and its implications for nucleosome binding. PUBMED:8384699 EPMC:8384699

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR005818




Proteins known to contain a H15 domain are:


This entry represents the H15 domain.

Gene Ontology


Domain organisation


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Pfam Clan



The clan contains the following 340 members:




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Curation and family details


Curation View help on the curation process

Seed source: Arne Eloffson
Previous IDs: linker_histone;
Type: Domain
Sequence Ontology: SO:0000417
Author: Bateman A
Number in seed: 275
Number in full: 4642
Average length of the domain: 69.40 aa
Average identity of full alignment: 30 %
Average coverage of the sequence by the domain: 22.80 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
Model details:
Parameter Sequence Domain
Gathering cut-off 22.4 22.4
Trusted cut-off 22.4 22.4
Noise cut-off 22.3 22.3
Model length: 74
Family (HMM) version: 19
Download: download the raw HMM for this family

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