Linked Life Data

16285826

Source:http://linkedlifedata.com/resource/pubmed/id/16285826

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
2005-11-15
pubmed:abstractText
One of the essential parts in the molecular mechanism of biological properties is the structural changes of proteins induced by stimuli. An amphiphilic copolymer, poly(L-leucine) grafted polyallylamine as a simple model of proteins, has been prepared by NCA polymerization with free amino groups of polyallylamine as an initiator. Here, we report the pH-induced reversible conformational and morphological regulation of the amphiphilic copolymer, whose hydrophobic peptide graft chains have no pH-sensitive groups, in an aqueous solution containing 50 vol % trifluoroethanol. The conformation of the poly(L-leucine) graft chain was found to be strongly pH dependent. Under acidic conditions, where electrostatic repulsion existed between the neighboring protonated amine moieties of the polyallylamine main chain, the rapid aggregation of the poly(l-leucine) graft chains was disturbed, and the peptide graft chains formed a beta-sheet structure owing to the intramolecular hydrogen bonding among the graft chains. Under this condition, the amphiphilic polymer formed amyloid-like fibrils, and then the fibrils grew into a planer plate composed of staked beta-sheets. On the other hand, under basic conditions, the poly(L-leucine) graft chains showed conformational transitions from a beta-sheet structure to an alpha-helical conformation owing to a distortion of the regular arrangement of the peptide graft chains by the conformational change of the polyallylamine main chain, whose amino groups were deprotonated. The conformational transition resulted in a disturbance of the regular sheet assembly of the amphiphilic copolymer and induced morphological changes to the amorphous globular aggregates. The pH-induced conformational and morphological changes of the poly(L-leucine) graft polyallylamine were reversible and synchronized with the protonation of the polyallylamine main chain.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0743-7463
pubmed:author
pubmed:issnType
Print
pubmed:day
22
pubmed:volume
21
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11462-7
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
pH-induced reversible conformational and morphological regulation of polyleucine grafted polyallylamine assembly in solution.
pubmed:affiliation
Department of Chemistry for Materials, Faculty of Engineering, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan. higuchi@chem.mie-u.ac.jp
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't