Linked Life Data

2241974

Source:http://linkedlifedata.com/resource/pubmed/id/2241974

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1990-12-5
pubmed:abstractText
Proline, noted as a hydrophilic residue with helix-breaking potential, nevertheless occurs widely in putatively alpha-helical transmembrane segments of many transport proteins. Ligand-activated or enzyme-assisted trans/cis isomerization of an X-proline peptide bond (where X = any amino acid)--a dynamic, reversible event which could alter the orientation of a transmembrane alpha-helix--may provide the molecular basis for a protein channel regulatory process. Further elucidation of such a function requires knowledge of the isomeric status of the X-Pro bonds in native conformations of membrane proteins. We have used 13C nuclear magnetic resonance (NMR) spectroscopy to examine the conformation of intramembranous X-Pro peptide bonds in biosynthetically-labelled samples of a model transport protein, bacteriorhodopsin (bR) (purple membrane). Spectra of 13C-Tyr-carbonyl labelled bR (in the solvent system CHCl3:CD3OD (1:1) + 0.1 M LiClO4) first established that all 11 bR Tyr residues were sufficiently mobile for their resonances to be detected and resolved, independent of their domain location within the bR sequence. By taking advantage of the known diagnostic chemical shifts of the isomers of Pro-C gamma carbon resonances, spectra of bR labelled with 13C gamma-Pro were then used to demonstrate that all 11 bR X-Pro peptide bonds--including those within the protein's membrane domain (Pro50, Pro91, Pro186)--are in the trans conformation in resting state bR.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-291X
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
172
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
862-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Conformation of proline residues in bacteriorhodopsin.
pubmed:affiliation
Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't