Linked Life Data

10760170

Source:http://linkedlifedata.com/resource/pubmed/id/10760170

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2000-5-23
pubmed:abstractText
In the chemotaxis of Escherichia coli, adaptation requires the methylation and demethylation of transmembrane receptors, which are catalysed by the methyltransferase CheR and the methylesterase CheB respectively. CheR binds to major chemoreceptors through their C-terminal motif NWETF, which is distinct from the methylation sites. In this study, we carried out a systematic mutagenesis of the pentapeptide sequence of Tar. Receptor methylation and adaptation were severely impaired by the alanine substitution of residue W550 and, to a lesser extent, by that of F553. Substitution of residues N549, E551 and T552 had only a slight or little effect. The defects of the W550A and F553A mutations were suppressed by high- and low-level overproduction of CheR respectively. Expression of a fusion protein containing the NWETF sequence, but not its W550A and F553A versions, inhibited chemotaxis of the Che+ strain. In an in vitro assay, CheR bound to the wild-type version but not to the mutant versions. These results and further mutagenesis suggest that the hydrophobicity and the size of residues W550 and F553 are critical in the interaction with CheR, a conclusion that is consistent with the crystal structure of a CheR-NWETF complex. On the other hand, the negatively charged side chain of E551 and the polar side chains of N549 and T552 may not be strictly required, although the presence of a salt bridge and hydrogen bonds between these residues and residues from CheR has been noted in the co-crystal.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
132-40
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
The aspartate chemoreceptor Tar is effectively methylated by binding to the methyltransferase mainly through hydrophobic interaction.
pubmed:affiliation
Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't