Enzymology of Inorganic Sulfate Metabolism
{'Code': '08070400', 'Directorate': {'Abbreviation': 'BIO', 'LongName': 'Direct For Biological Sciences'}, 'Division': {'Abbreviation': 'MCB', 'LongName': 'Div Of Molecular and Cellular Bioscience'}}
{'SignBlockName': 'Parag R. Chitnis', 'PO_EMAI': None, 'PO_PHON': None}
Most bacteria, yeast, fungi, algae and higher plants can use                    inorganic sulfate as their sole source of sulfur for the                        biosynthesis of cysteine, methionine, and a variety of organic                  sulfur-containing coenzymes.  The objective of this research is                 to establish the structure-function relationships of the                        enzymes which catalyze the early steps of sulfate assimilation.                 The enzymes ATP  Sulfurylase, APS kinase, and PAPS reductase                    will be studied.  The first two catalyze the two-step ATP-                      dependent "activation" of  S042- forming 3'- phosphoadenosine-                  5' -phosphosulfate (PAPS).  The last named enzyme (actually a                   multicomponent system) catalyzes the NADPH- and thioredoxin-                    dependent reduction of PAPS to inorganic sulfite.  Specific                     aims include (a) determining the kinetic and chemical                           mechanisms, (b) identifying aminoacyl residues at the active                    site, and (c) exploring the potential interaction of the two                    sulfate activating enzymes to form a "PAPS synthetase" complex.                                                                                                 The experiments will be conducted with enzymes purified from                    the filamentous fungus Penicillium chrysogenum and from spinach                 leaf.  Parallel studies will be performed on the enzymes from                   P.  duponti (a thermophile) with the objective of identifying                   the structural features responsible for the remarkable heat                     stability of thermophile enzymes.  Enzyme kinetics, protein                     chemistry, and molecular biology methods will be used.                                                                                                          Inorganic sulfate is reduced to a state suitable for                            incorporation into sulfur containing amino acids and other                      factors by a complex pathway in plants and microorganizms.  The                 investigator employs a sophisticated mathematical approach to                   the study of these enzymes.  He wishes to analyze the chemical                  mechanisms by which they carry out the reactions involved.
{'FirstName': 'Irwin', 'LastName': 'Segel', 'PI_MID_INIT': 'H', 'PI_SUFX_NAME': None, 'PI_FULL_NAME': 'Irwin H Segel', 'EmailAddress': 'ihsegel@ucdavis.edu', 'NSF_ID': '000148980', 'StartDate': '09/01/1988', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'University of California-Davis', 'CityName': 'DAVIS', 'ZipCode': '956186153', 'PhoneNumber': '5307547700', 'StreetAddress': '1850 RESEARCH PARK DR STE 300', 'StreetAddress2': None, 'CountryName': 'United States', 'StateName': 'California', 'StateCode': 'CA', 'CONGRESSDISTRICT': '04', 'CONGRESS_DISTRICT_ORG': 'CA04', 'ORG_UEI_NUM': 'TX2DAGQPENZ5', 'ORG_LGL_BUS_NAME': 'UNIVERSITY OF CALIFORNIA, DAVIS', 'ORG_PRNT_UEI_NUM': 'NUDGYLBB4S99'}
{'Name': None, 'CityName': None, 'StateCode': None, 'ZipCode': None, 'StreetAddress': None, 'CountryCode': None, 'CountryName': None, 'StateName': None, 'CountryFlag': None, 'CONGRESSDISTRICT': None, 'CONGRESS_DISTRICT_PERF': '""'}
[{'Code': '1144', 'Text': 'Molecular Biophysics'}, {'Code': '9145', 'Text': 'SPECIAL PROGRAMS-RESERVE'}]
{'url': 'https://www.nsf.gov/awardsearch/download?DownloadFileName=1988&All=true', 'xml': '8802731.xml'}