Biosynthesis of the iron-molybdenum cofactor and the molybdenum cofactor in Klebsiella pneumoniae: effect of sulfur source
NifQ/sup -/ and Mol/sup -/ mutants of Klebsiella pneumoniae show an elevated molybdenum requirement for nitrogen fixation. Substitution of cystine for sulfate as the sulfur source in the medium reduced the molybdenum requirement of these mutants to levels required by the wild type. Cystine also increased the intracellular molybdenum accumulation of NifQ/sup -/ and Mol/sup -/ mutants. Cystine did not affect the molybdenum requirement or accumulation in wild-type K. pneumoniae. Sulfate transport and metabolism in K. pneumoniae were repressed by cystine. However, the effect of cystine on the molybdenum requirement could not be explained by an interaction between sulfate and molybdate at the transport level. The data show that cystine does not have a generalized effect on molybdenum metabolism. Millimolar concentrations of molybdate inhibited nitrogenase and nitrate reductase derepression with sulfate as the sulfur source, but not with cystine. The inhibition was the result of a specific antagonism of sulfate metabolism by molybdate. This study suggests that a sulfur donor and molybdenum interact at an early step in the biosynthesis of the iron-molybdenum cofactor. This interaction might occur nonenzymatically when the levels of the reactants are high.
- Research Organization:
- Univ. of Wisconsin, Madison
- OSTI ID:
- 5449608
- Journal Information:
- J. Bacteriol.; (United States), Vol. 164:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
COENZYMES
BIOSYNTHESIS
MOLYBDATES
METABOLISM
MOLYBDENUM 99
SODIUM SULFATES
SULFUR 35
CYSTINE
KLEBSIELLA
MEMBRANE TRANSPORT
ALKALI METAL COMPOUNDS
AMINO ACIDS
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
DISULFIDES
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
ISOTOPES
LIGHT NUCLEI
MICROORGANISMS
MOLYBDENUM COMPOUNDS
MOLYBDENUM ISOTOPES
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
OXYGEN COMPOUNDS
RADIOISOTOPES
REFRACTORY METAL COMPOUNDS
SODIUM COMPOUNDS
SULFATES
SULFUR COMPOUNDS
SULFUR ISOTOPES
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
550601* - Medicine- Unsealed Radionuclides in Diagnostics
550201 - Biochemistry- Tracer Techniques
550701 - Microbiology- Tracer Techniques