Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
38
pubmed:dateCreated
2003-9-23
pubmed:abstractText
Two cysteines separated by two other residues (the CxxC motif) are employed by many redox proteins for formation, isomerization, and reduction of disulfide bonds and for other redox functions. The place of the C-terminal cysteine in this motif may be occupied by serine (the CxxS motif), modifying the functional repertoire of redox proteins. Here we found that the CxxC motif may also give rise to a motif, in which the C-terminal cysteine is replaced with threonine (the CxxT motif). Moreover, in contrast to a view that the N-terminal cysteine in the CxxC motif always serves as a nucleophilic attacking group, this residue could also be replaced with threonine (the TxxC motif), serine (the SxxC motif), or other residues. In each of these CxxC-derived motifs, the presence of a downstream alpha-helix was strongly favored. A search for conserved CxxC-derived motif/helix patterns in four complete genomes representing bacteria, archaea, and eukaryotes identified known redox proteins and suggested possible redox functions for several additional proteins. Catalytic sites in peroxiredoxins were major representatives of the TxxC motif, whereas those in glutathione peroxidases represented the CxxT motif. Structural assessments indicated that threonines in these enzymes could stabilize catalytic thiolates, suggesting revisions to previously proposed catalytic triads. Each of the CxxC-derived motifs was also observed in natural selenium-containing proteins, in which selenocysteine was present in place of a catalytic cysteine.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
42
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11214-25
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:14503871-Amino Acid Motifs, pubmed-meshheading:14503871-Amino Acid Sequence, pubmed-meshheading:14503871-Animals, pubmed-meshheading:14503871-Bacterial Proteins, pubmed-meshheading:14503871-Catalytic Domain, pubmed-meshheading:14503871-Conserved Sequence, pubmed-meshheading:14503871-Cysteine, pubmed-meshheading:14503871-Genome, Bacterial, pubmed-meshheading:14503871-Glutathione Peroxidase, pubmed-meshheading:14503871-Humans, pubmed-meshheading:14503871-Mice, pubmed-meshheading:14503871-Models, Molecular, pubmed-meshheading:14503871-Molecular Sequence Data, pubmed-meshheading:14503871-Oxidation-Reduction, pubmed-meshheading:14503871-Peroxidases, pubmed-meshheading:14503871-Proteins, pubmed-meshheading:14503871-Saccharomyces cerevisiae Proteins, pubmed-meshheading:14503871-Selenoproteins, pubmed-meshheading:14503871-Sequence Alignment, pubmed-meshheading:14503871-Sequence Homology, Amino Acid, pubmed-meshheading:14503871-Thioredoxins
pubmed:year
2003
pubmed:articleTitle
Identity and functions of CxxC-derived motifs.
pubmed:affiliation
Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.