Linked Life Data

15546995

Source:http://linkedlifedata.com/resource/pubmed/id/15546995

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
47
pubmed:dateCreated
2004-11-24
pubmed:abstractText
Conformational studies on the synthetic 11-aa peptide t-butoxycarbonyl (Boc)-Val-Ala-Phe-alpha-aminoisobutyric acid (Aib)-(R)-beta3-homovaline (betaVal)-(S)-beta3-homophenylalanine (betaPhe)-Aib-Val-Ala-Phe-Aib-methyl ester (OMe) (peptide 1; betaVal and betaPhe are beta amino acids generated by homologation of the corresponding l-residues) establish that insertion of two consecutive beta residues into a polypeptide helix can be accomplished without significant structural distortion. Crystal-structure analysis reveals a continuous helical conformation encompassing the segment of residues 2-10 of peptide 1. At the site of insertion of the betabeta segment, helical hydrogen-bonded rings are expanded. A C15 hydrogen bond for the alphabetabeta segment and two C14 hydrogen bonds for the alphaalphabeta or betaalphaalpha segments have been characterized. The following conformational angles were determined from the crystal structure for the beta residues: betaVal-5 (= -126 degrees, = 76 degrees, and psi = -124) and betaPhe-6 (=-88 degrees, = 80 degrees, and psi =-118). The N terminus of the peptide is partially unfolded in crystals. The 500-MHz 1H-NMR studies establish a continuous helix over the entire length of the peptide in CDCl3 solution, as evidenced by diagnostic nuclear Overhauser effects. The presence of seven intramolecular hydrogen bonds is also established by using solvent dependence of NH chemical shifts.
pubmed:grant
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0027-8424
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
101
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
16478-82
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Alpha,beta hybrid peptides: a polypeptide helix with a central segment containing two consecutive beta-amino acid residues.
pubmed:affiliation
Molecular Biophysics Unit and Sophisticated Instruments Facility, Indian Institute of Science, Bangalore 560012, India.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't