Molybdopterin biosynthesis: Role of the chlN gene product
- Duke Univ., Durham, NC (United States)
Molybdopterin (MPT) is a unique sulfur containing pterin that binds molybdenum in all molybdenum enzymes except nitrogenase. In E. coli MPT is produced in a stoichiometric reaction from a desulfo pterin precursor by a protein complex called converting factor which is encoded at genes 4 and 5 of the chlA locus. This activity is absent in chlA mutants affected at genes 4 or 5 and in the chlN mutant. In vitro complementation studies suggested the small subunit of converting factor (the chlA gene 4 product) was present in an inactive form in chlN, implicating chlN in its activation. As a first step in determining the role of the chlN gene in the formation of active converting factor, the authors purified the inactive converting factor from chlN extract and demonstrated that both converting factor proteins are produced in chlN cells. A plasmid capable of complementing chlN was used to overexpress the chlN gene product in a chlA mutant lacking the small subunit of converting factor. In this system the activity of the chlN gene product could be assayed by the in vitro complementation of chlN extract. Iodoacetamide, which abolishes converting factor activity by reacting with the small subunit, has no effect on the ability of chlN converting factor to be activated by the chlN gene product. This suggests the chlN gene product plays a role in creating the reactive sulfur on the small subunit of converting factor.
- OSTI ID:
- 5265828
- Report Number(s):
- CONF-9104107-; CODEN: FAJOE
- Journal Information:
- FASEB Journal (Federation of American Societies for Experimental Biology); (United States), Vol. 5:4; Conference: 75. annual meeting of the Federation of American Societies for Experimental Biology (FASEB), Atlanta, GA (United States), 21-25 Apr 1991; ISSN 0892-6638
- Country of Publication:
- United States
- Language:
- English
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METALLOPROTEINS
BIOSYNTHESIS
MOLYBDENUM
METABOLISM
ESCHERICHIA COLI
GENES
MUTANTS
PROTEINS
STOICHIOMETRY
BACTERIA
ELEMENTS
METALS
MICROORGANISMS
ORGANIC COMPOUNDS
SYNTHESIS
TRANSITION ELEMENTS
560300* - Chemicals Metabolism & Toxicology