Linked Life Data

1610821

Source:http://linkedlifedata.com/resource/pubmed/id/1610821

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
25
pubmed:dateCreated
1992-7-28
pubmed:abstractText
Poly(L-lysine) exists as a random-coil at neutral pH, an alpha-helix at alkaline pH, and a beta-sheet when the alpha-helix poly(L-lysine) is heated. The present Fourier-transform infrared (FTIR) study showed that short-chain alcohols (methanol, ethanol, and 2-propanol) partially transformed alpha-helix poly(L-lysine) to beta-sheet when their concentrations were low. At higher concentrations, however, these alcohols reversed the reaction, and the alcohol-induced beta-sheet was transformed back to alpha-helix structure. The reversal occurred at 1.40 M methanol, 0.96 M ethanol, and 0.55 M 2-propanol. The alcohol effects on the secondary structure were further investigated by circular dichroism (CD) on the thermally induced beta-sheet poly(L-lysine). Methanol, ethanol, and 1-propanol, but not 1-butanol, shifted the negative mean-residue ellipticity at 217 nm of the beta-sheet poly(L-lysine) to the positive side at low concentrations of the alcohols and to the negative side at high concentrations. With 1-butanol, only the positive-side shift was observed. The positive-side shift at low concentrations of alcohols indicates enhancement of the hydrophobic interactions among the side chains of the polypeptide in the beta-sheet conformation. The negative-side shift indicates a partial transformation to alpha-helix. The shift from the positive to negative side occurred at 7.1 M methanol, 4.6 M ethanol, and 3.1 M 1-propanol. The alcohol concentrations for the beta-to-alpha transition were higher in the CD study than in the IR study.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5728-33
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Biphasic effects of alcohols on the phase transition of poly(L-lysine) between alpha-helix and beta-sheet conformations.
pubmed:affiliation
Faculty of Pharmaceutical Sciences, Tokushima University, Japan.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.