Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1992-11-12
pubmed:abstractText
The effects of N-ethylmaleimide (NEM) and other sulfhydryl modifiers on the structure of skinned frog skeletal muscles were studied using the X-ray diffraction technique. In sartorius muscle with full overlap between the thick and thin filaments, 0.1-1.0 mM NEM changed the intensity ratio of the (1,0) and (1,1) equatorial reflections from 4.35 to 0.72, and the (1,0) spacing of the hexagonal filament lattice from 40.4 to 41.4 nm. The axial X-ray diffraction pattern showed weak myosin layer-lines after the NEM treatment but enhancement of the actin layer-lines was not observed. In overstretched semitendinosus muscle, NEM did not affect the equatorial spacing but the myosin layer-lines were weakened. These results indicate that modification of myosin by NEM destroys the helical arrangement of myosin heads around the shaft of the thick filament and that when thin filaments are available, myosin heads move towards, and possibly bind to them. This binding is different from that in rigor since the 'ladder-like' appearance of the higher actin layer-lines, which is typical of patterns from rigor muscles, was not observed. On removal of ATP after the NEM treatment, the diffraction pattern showed features characteristic of that from normal rigor muscles but no tension was produced. The pattern showed well-defined samplings on layer-lines in the small-angle region, indicating the presence of an extensive lattice order and exact axial alignment of the filaments. The first actin layer-line did not show samplings from the superlattice of the thick filaments, which are observed on the myosin layer-lines in patterns from resting muscles.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0142-4319
pubmed:author
pubmed:issnType
Print
pubmed:volume
13
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
457-63
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Effects of N-ethylmaleimide on the structure of skinned frog skeletal muscles.
pubmed:affiliation
Department of Pharmacology, Tohoku University School of Medicine, Sendai, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't