Linked Life Data

2166562

Source:http://linkedlifedata.com/resource/pubmed/id/2166562

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
24
pubmed:dateCreated
1990-9-14
pubmed:abstractText
We have used electron paramagnetic resonance (EPR) to determine the effects of ADP on the orientational distribution of nitroxide spin labels attached to myosin heads in skinned rabbit psoas muscle fibers. To maximize the specificity of labeling, we spin-labeled isolated myosin heads (subfragment 1) on a single reactive thiol (SH1) and diffused them into unlabeled muscle fibers. To maximize spectral and orientational resolution, we used perdeuterated spin labels, 2H-MSL and 2H-IASL, eliminating superhyperfine broadening and thus narrowing the line widths. Two different spin labels were used, with different orientation relative to the myosin head, to ensure that the results are not affected by unfavorable probe orientation. In rigor, a very narrow three-line spectrum was observed for both spin labels, indicating a narrow orientational distribution, as reported previously (Thomas & Cooke, 1980). ADP induced very slight changes in the spectrum, corresponding to very slight (but significant) changes in the orientational distribution. These changes were quantified by a digital analysis of the spectra, using a two-step simplex fitting procedure (Fajer et al., 1990). First, the magnetic tensor values and line widths were determined by fitting the spectrum of a randomly oriented sample. Then the spectrum of oriented fibers was fit to a model by assuming a Gaussian distribution of the tilt angle (theta) and twist angle (phi) of the nitroxide principal axes relative to the fiber axis. A single-Gaussian distribution resulted in inadequate fits, but a two-component model gave excellent results. ADP induces a small (less than 5 degrees) rotation of the major components for both spin labels, along with a similarly small increase of disorder about the average positions.
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
19
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5865-71
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Effect of ADP on the orientation of spin-labeled myosin heads in muscle fibers: a high-resolution study with deuterated spin labels.
pubmed:affiliation
Department of Biochemistry, University of Minnesota Medical School, Minneapolis 55455.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't