Open AccessBiosynthesis of molybdoenzymes in E. coli: chlB is the only chlorate resistance locus required for protein FA activity
Author(s) -
Low Donald C.,
Pommier Janine,
Giordano Gerard,
Boxer David H.
Publication year - 1988
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1988.tb02752.x
Subject(s) - molybdenum cofactor , chlorate , mutant , biochemistry , chemistry , cofactor , escherichia coli , nitrate reductase , biosynthesis , periplasmic space , enzyme , gene , inorganic chemistry
The chlorate resistance mutants are pleitropically defective in the activity of all molybdoenzymes in Escherichia coli . Protein FA addition to the soluble fraction of a chlB mutant, brings about the activation of the molybdoenzyme, respiratory nitrate reductase, an inactive precursor of which is present in the chlB fraction. The rate of the activation process but not its extent is dependent upon the quantity of protein FA present. Protein FA activity is constitutively expressed and was present in normal amounts in chlA, D, E, F and G mutants but was absent from all chlB strains examined. This is consistent with protein FA being the active product of the chlB locus. Sodium tungstate (10 mM) in the growth medium has no effect on protein FA activity. Protein FA does not function as a source of molybdenum cofactor activity in the activation process.