Linked Life Data

11814339

Source:http://linkedlifedata.com/resource/pubmed/id/11814339

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2002-1-29
pubmed:abstractText
A 30-residue nitroxide scan encompassing a helical hairpin and an extended loop in soluble annexin 12 (helices D and E in repeat 2; residues 134-163) has been analyzed in terms of nitroxide side chain mobility and accessibility to collision with paramagnetic reagents (Pi). Values of Pi for both O(2) and a Ni(II) metal complex (NiEDDA) are remarkably well correlated with the fractional solvent accessibility of the native side chains at the corresponding positions computed from the known crystal structure. This result demonstrates the utility of Pi as an experimental measure of side chain accessibility in solution, as well as the lack of structural perturbation due to the presence of the nitroxide side chain. The pattern of side chain mobility is also in excellent agreement with predictions from the crystal structure. The results presented here extend the correlations between mobility and structure described in earlier work on other helical proteins, and suggest their generality. The periodic dependence of Pi and mobility along the sequence of annexin 12 reveals the helical segments and their orientation in the fold, as expected for a nonperturbing nitroxide side chain. However, these data do not distinguish the helix-loop-helix motif from a continuous helix, because immobilized side chains in the short loop sequence maintain the periodicity. As shown here, the ratio of Pi values for O(2) and NiEDDA clearly delineates the loop region, due to size exclusion effects between the two reagents. A new feature evident in a nitroxide scan through multiple secondary elements is a modulation of the basic Pi and mobility patterns along the sequence, apparently due to differences in helix packing and backbone motion. Thus, in the short helix D, residues are consistently more mobile and accessible throughout the sequence compared to the residues in the longer, less-solvated and more ordered helix E.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
41
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1464-73
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Structure and dynamics of a helical hairpin and loop region in annexin 12: a site-directed spin labeling study.
pubmed:affiliation
Department of Physiology and Biophysics, University of California, Irvine, California 92697, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't