Linked Life Data

10461744

Source:http://linkedlifedata.com/resource/pubmed/id/10461744

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1999-10-12
pubmed:abstractText
The effect of hexafluoroacetone hydrate (HFA) on the structure of the honey bee venom peptide melittin has been investigated. In aqueous solution at low pH melittin is predominantly unstructured. Addition of HFA at pH approximately 2.0 induces a structural transition from the unstructured state to a predominantly helical conformation as suggested by intense diagnostic far UV CD bands. The structural transition is highly cooperative and complete at 3.6 M (50% v/v) HFA. A similar structural transition is also observed in 2,2,2 trifluoroethanol which is complete only at a cosolvent concentration of approximately 8 M. Temperature dependent CD experiments support a 'cold denaturation' of melittin at low concentrations of HFA, suggesting that selective solvation of peptide by HFA is mediated by hydrophobic interactions. NMR studies in 3.6 M HFA establish a well-defined helical structure of melittin at low pH, as suggested by the presence of strong NH/NHi+1 NOEs throughout the sequence, along with many medium range helical NOEs. Structure calculations using NOE-driven distance constraints reveal a well-ordered helical fold with a relatively flexible segment around residues T10-G11-T12. The helical structure of melittin obtained at 3.6 M HFA at low pH is similar to those determined in methanolic solution and perdeuterated dodecylphosphocholine micelles. HFA as a cosolvent facilitates helix formation even in the highly charged C-terminal segment.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1397-002X
pubmed:author
pubmed:issnType
Print
pubmed:volume
54
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
100-11
pubmed:dateRevised
2000-12-18
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Fluoroalcohols as structure modifiers in peptides and proteins: hexafluoroacetone hydrate stabilizes a helical conformation of melittin at low pH.
pubmed:affiliation
Molecular Biophysics Unit, Indian Institute of Science, Bangalore.
pubmed:publicationType
Journal Article