Linked Life Data

7578012

Source:http://linkedlifedata.com/resource/pubmed/id/7578012

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
43
pubmed:dateCreated
1995-12-15
pubmed:abstractText
The known high-resolution structure and dynamics characterization of the lipid bilayer-bound polypeptide gramicidin A provides a unique opportunity to study structure-function and dynamics-function correlations in a model membrane protein. In particular, the indoles have a variety of very important functional roles in this cation channel that will undoubtedly be recognized in membrane proteins. That indoles and phenols are oriented at the hydrophobic-hydrophilic interface of lipid bilayers is already well-recognized in membrane proteins. The most buried indole of the gramicidin channel, Trp9, is shown by 15N solid state NMR to be exposed to the hydrophilic surface through hydrogen exchange. Here the importance of the indole dipole moments is described for cation conductance. Preparation of samples with high concentrations of Na+ is shown by high-resolution orientational constraints derived from 2H NMR to have no structural effect on the indole side chain conformations. These dipoles stabilize cations in the binding sites near the channel entrance and substantially reduce the potential energy barrier at the bilayer center. This latter finding conclusively documents that the rate-limiting step in cation conductance by this channel involves the barrier at the bilayer center. Furthermore, dynamics of the indole rings cause significant fluctuations in the energy of stabilization at the binding site that may result in a rapid mechanism for gating the channel.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
31
pubmed:volume
34
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14147-55
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Tryptophan hydrogen bonding and electric dipole moments: functional roles in the gramicidin channel and implications for membrane proteins.
pubmed:affiliation
Center for Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, Florida State University, Tallahassee 32306, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't