Linked Life Data

10828978

Source:http://linkedlifedata.com/resource/pubmed/id/10828978

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
2000-7-10
pubmed:abstractText
AhpF, the flavin-containing component of the Salmonella typhimurium alkyl hydroperoxide reductase system, catalyzes the NADH-dependent reduction of an active-site disulfide bond in the other component, AhpC, which in turn reduces hydroperoxide substrates. The amino acid sequence of the C-terminus of AhpF is 35% identical to that of thioredoxin reductase (TrR) from Escherichia coli. AhpF contains an additional 200-residue N-terminal domain possessing a second redox-active disulfide center also required for AhpC reduction. Our studies indicate that this N-terminus contains a tandem repeat of two thioredoxin (Tr)-like folds, the second of which contains the disulfide redox center. Structural and catalytic properties of independently expressed fragments of AhpF corresponding to the TrR-like C-terminus (F[208-521]) and the 2Tr-like N-terminal domain (F[1-202]) have been addressed. Enzymatic assays, reductive titrations, and circular dichroism studies of the fragments indicate that each folds properly and retains many functional properties. Electron transfer between F[208-521] and F[1-202] is, however, relatively slow (4 x 10(4) M(-)(1) s(-)(1) at 25 degrees C) and nonsaturable up to 100 microM F[1-202]. TrR is nearly as efficient at F[1-202] reduction as is F[208-521], although neither the latter fragment, nor intact AhpF, can reduce Tr. An engineered mutant AhpC substrate with a fluorophore attached via a disulfide bond has been used to demonstrate that only F[1-202], and not F[208-521], is capable of electron transfer to AhpC, thereby establishing the direct role this N-terminal domain plays in mediating electron transfer between the TrR-like part of AhpF and AhpC.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
6
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6602-15
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:10828978-Amino Acid Sequence, pubmed-meshheading:10828978-Bacterial Proteins, pubmed-meshheading:10828978-Circular Dichroism, pubmed-meshheading:10828978-Disulfides, pubmed-meshheading:10828978-Electron Transport, pubmed-meshheading:10828978-Escherichia coli Proteins, pubmed-meshheading:10828978-Fluorescent Dyes, pubmed-meshheading:10828978-Models, Molecular, pubmed-meshheading:10828978-Molecular Sequence Data, pubmed-meshheading:10828978-Mutagenesis, pubmed-meshheading:10828978-Peptide Fragments, pubmed-meshheading:10828978-Peroxidases, pubmed-meshheading:10828978-Peroxiredoxins, pubmed-meshheading:10828978-Protein Structure, Secondary, pubmed-meshheading:10828978-Salmonella typhimurium, pubmed-meshheading:10828978-Sequence Alignment, pubmed-meshheading:10828978-Spectrophotometry, pubmed-meshheading:10828978-Tandem Repeat Sequences, pubmed-meshheading:10828978-Thioredoxin-Disulfide Reductase, pubmed-meshheading:10828978-Ultracentrifugation
pubmed:year
2000
pubmed:articleTitle
AhpF can be dissected into two functional units: tandem repeats of two thioredoxin-like folds in the N-terminus mediate electron transfer from the thioredoxin reductase-like C-terminus to AhpC.
pubmed:affiliation
Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA. lbpoole@wfubmc.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't