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Title: Biosynthesis of the iron-molybdenum cofactor and the molybdenum cofactor in Klebsiella pneumoniae: effect of sulfur source

Abstract

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.

Authors:
; ; ;
Publication Date:
Research Org.:
Univ. of Wisconsin, Madison
OSTI Identifier:
5449608
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Bacteriol.; (United States); Journal Volume: 164:3
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 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

Citation Formats

Ugalde, R.A., Imperial, J., Shah, V.K., and Brill, W.J.. Biosynthesis of the iron-molybdenum cofactor and the molybdenum cofactor in Klebsiella pneumoniae: effect of sulfur source. United States: N. p., 1985. Web.
Ugalde, R.A., Imperial, J., Shah, V.K., & Brill, W.J.. Biosynthesis of the iron-molybdenum cofactor and the molybdenum cofactor in Klebsiella pneumoniae: effect of sulfur source. United States.
Ugalde, R.A., Imperial, J., Shah, V.K., and Brill, W.J.. Sun . "Biosynthesis of the iron-molybdenum cofactor and the molybdenum cofactor in Klebsiella pneumoniae: effect of sulfur source". United States.
@article{osti_5449608,
title = {Biosynthesis of the iron-molybdenum cofactor and the molybdenum cofactor in Klebsiella pneumoniae: effect of sulfur source},
author = {Ugalde, R.A. and Imperial, J. and Shah, V.K. and Brill, W.J.},
abstractNote = {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.},
doi = {},
journal = {J. Bacteriol.; (United States)},
number = ,
volume = 164:3,
place = {United States},
year = {Sun Dec 01 00:00:00 EST 1985},
month = {Sun Dec 01 00:00:00 EST 1985}
}