Linked Life Data

2550423

Source:http://linkedlifedata.com/resource/pubmed/id/2550423

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
27
pubmed:dateCreated
1989-10-25
pubmed:databankReference
pubmed:abstractText
NADPH-sulfite reductase flavoprotein (SiR-FP) was purified from a Salmonella typhimurium cysG strain that does not synthesize the hemoprotein component of the sulfite reductase holoenzyme. cysJ, which codes for SiR-FP, was cloned from S. typhimurium LT7 and Escherichia coli B, and both genes were sequenced. Physicochemical analyses and deduced amino acid sequences indicate that SiR-FP is an octamer of identical 66-kDa peptides and contains 4 FAD and 4 FMN per octamer. Potentiometric titrations of SiR holoenzyme, SiR-FP, and FMN-depleted SiR-FP yielded the following redox potentials for the prosthetic groups at pH 7.7: E'1 (FMNH./FMN) = -152 mV; E'2 (FMNH2/FMNH.) = -327 mV; E'3 (FADH./FAD) = -382 mV; E'4 (FADH2/FADH.) = -322 mV. Microcoulometric titration of SiR-FP at 25 degrees C yielded data which were in full agreement with these potentials. Spectroscopic and catalytic studies of native SiR-FP and of SiR-FP depleted of FMN support the following electron flow sequence: NADPH----FAD----FMN. FMN can then contribute electrons to the hemoprotein component of sulfite reductase, as well as to cytochrome c and various diaphorase acceptors. The FMN is postulated to cycle between the FMNH2 and FMNH. oxidation states during catalysis; in this sense SiR-FP shares a catalytic mechanism with NADPH-cytochrome P-450 oxidoreductase. SiR-FP domains involved in binding FMN, FAD, and NADPH are proposed from amino acid sequence homologies with Desulfovibrio vulgaris flavodoxin (Dubourdieu, M., and Fox, J.L. (1977) J. Biol. Chem. 252, 1453-1463) and spinach ferredoxin-NADP+ oxidoreductase (Karplus, P.A., Walsh, K.A., and Herriott, J. R. (1984) Biochemistry 23, 6576-6583). Comparison of the deduced amino acid sequences of SiR-FP and NADPH-cytochrome P-450 oxidoreductase (Porter, T. D., and Kasper, C.B. (1985) Proc. Natl. Acad. Sci. U. S.A. 82, 973-977) also showed identities that suggest these two proteins are descended from a common precursor, which contained binding regions for both FMN and FAD.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
264
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15796-808
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:2550423-Amino Acid Sequence, pubmed-meshheading:2550423-Base Sequence, pubmed-meshheading:2550423-Electron Spin Resonance Spectroscopy, pubmed-meshheading:2550423-Escherichia coli, pubmed-meshheading:2550423-Flavoproteins, pubmed-meshheading:2550423-Genes, pubmed-meshheading:2550423-Genes, Bacterial, pubmed-meshheading:2550423-Kinetics, pubmed-meshheading:2550423-Molecular Sequence Data, pubmed-meshheading:2550423-Oxidoreductases, pubmed-meshheading:2550423-Oxidoreductases Acting on Sulfur Group Donors, pubmed-meshheading:2550423-Peptide Fragments, pubmed-meshheading:2550423-Plasmids, pubmed-meshheading:2550423-Restriction Mapping, pubmed-meshheading:2550423-Salmonella typhimurium, pubmed-meshheading:2550423-Sequence Homology, Nucleic Acid, pubmed-meshheading:2550423-Spectrophotometry, pubmed-meshheading:2550423-Sulfite Reductase (NADPH)
pubmed:year
1989
pubmed:articleTitle
Characterization of the flavoprotein moieties of NADPH-sulfite reductase from Salmonella typhimurium and Escherichia coli. Physicochemical and catalytic properties, amino acid sequence deduced from DNA sequence of cysJ, and comparison with NADPH-cytochrome P-450 reductase.
pubmed:affiliation
Howard Hughes Medical Institute Laboratory, Duke University Medical Center, Durham, North Carolina 27710.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.