Linked Life Data

12581649

Source:http://linkedlifedata.com/resource/pubmed/id/12581649

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2003-2-12
pubmed:databankReference
pubmed:abstractText
Adjacent N11L and L12N mutations in the antiparallel beta-ribbon of Arc repressor result in dramatic changes in local structure in which each beta-strand is replaced by a right-handed helix. The full solution structure of this "switch" Arc mutant shows that irregular 3(10) helices compose the new secondary structure. This structural metamorphosis conserves the number of main-chain and side-chain to main-chain hydrogen bonds and the number of fully buried core residues. Apart from a slight widening of the interhelical angle between alpha-helices A and B and changes in side-chain conformation of a few core residues in Arc, no large-scale structural adjustments in the remainder of the protein are necessary to accommodate the ribbon-to-helix change. Nevertheless, some changes in hydrogen-exchange rates are observed, even in regions that have very similar structures in the two proteins. The surface of switch Arc is packed poorly compared to wild-type, leading to approximately 1000A(2) of additional solvent-accessible surface area, and the N termini of the 3(10) helices make unfavorable head-to-head electrostatic interactions. These structural features account for the positive m value and salt dependence of the ribbon-to-helix transition in Arc-N11L, a variant that can adopt either the mutant or wild-type structures. The tertiary fold is capped in different ways in switch and wild-type Arc, showing how stepwise evolutionary transformations can arise through small changes in amino acid sequence.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0022-2836
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
326
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
899-909
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Solution structure of switch Arc, a mutant with 3(10) helices replacing a wild-type beta-ribbon.
pubmed:affiliation
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, MA, USA. cordes@email.arizona.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't