Linked Life Data

12022866

Source:http://linkedlifedata.com/resource/pubmed/id/12022866

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
2002-5-22
pubmed:abstractText
EmrE, a multidrug resistance protein from Escherichia coli, renders the bacterium resistant to a variety of cytotoxic drugs by active translocation out of the cell. The 110-residue sequence of EmrE limits the number of structural possibilities that can be envisioned for this membrane protein. Four helix bundle models have been considered [Yerushalmi, H., Lebendiker, M., and Schuldiner, S. (1996) J. Biol. Chem. 271, 31044-31048]. The validity of EmrE structural models has been probed experimentally by investigations on overlapping peptides (ranging in length from 19 to 27 residues), derived from the sequence of EmrE. The choice of peptides was made to provide sequences of two complete, predicted transmembrane helices (peptides H1 and H3) and two helix-loop-helix motifs (peptides A and B). Peptide (B) also corresponds to a putative hairpin in a speculative beta-barrel model, with the "Pro-Thr-Gly" segment forming a turn. Structure determination in SDS micelles using NMR indicates peptide H1 to be predominantly helical, with helix boundaries in the micellar environment corroborating predicted helical limits. Peptide A adopts a helix-loop-helix structure in SDS micelles, and peptide B was also largely helical in micellar environments. An analogue peptide, C, in which the central "Pro-Thr-Gly" was replaced by "(D)Pro-Gly" displays local turn conformation at the (D)Pro-Gly segment, but neither a continuous helical stretch nor beta-hairpin formation was observed. This study implies that the constraints of membrane and micellar environments largely direct the structure of transmembrane peptides and proteins and study of judiciously selected peptide fragments can prove useful in the structural elucidation of membrane proteins.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
41
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6631-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Structural analysis of synthetic peptide fragments from EmrE, a multidrug resistance protein, in a membrane-mimetic environment.
pubmed:affiliation
Molecular Biophysics Unit and Sophisticated Instruments Facility, Indian Institute of Science, Bangalore 560 012, India.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't