Linked Life Data

7787067

Source:http://linkedlifedata.com/resource/pubmed/id/7787067

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4 Suppl
pubmed:dateCreated
1995-7-27
pubmed:abstractText
It has been shown that in solution myosin subfragment 1 binds to actin in three principal steps: [formula: see text] The nucleotide bound to myosin has a major influence on the equilibrium constant of the third of these steps but little effect on the other two. The third step is thought to be coupled to the force-generating event. Three-step binding and structure: The formation of the collision complex is strongly ionic strength dependent but independent of temperature. The isomerization to the A state is not strongly dependent on ionic strength but is affected by organic solvent and temperature. In contrast the isomerization to the R state-is affected by both ionic strength and organic solvent but little affected by temperature. The recent docking of the three-dimensional structures of actin and S1 suggest possible structural correlates of these events. These studies lead to predictions for the docking process, which may be tested using site-directed mutagenesis or peptide inhibitors. Three-step binding and head-head interactions: Studies of HMM binding to actin compared with S1 binding show that binding of two heads in the A state are unlikely presumably because of strain effects. However, binding of two heads as one A and one R state shows little evidence of strain while the isomerization of the second head to give two R states is fivefold weaker than for an isolated S1 head. These results suggest that in a rapidly shortening muscle only one head is likely to be attached at a time. Under isometric conditions, although it is possible for both heads to bind to adjacent actins, it is unlikely that both will be in the force holding R state simultaneously. Three-step binding and regulation by tropomyosin-troponin:Our recent solution studies have established that the thin filament can exist in three calcium-dependent states which we termed blocked, closed and open. A blocked state cannot form the A state with S1 and a closed state cannot form the force holding R state nor accelerate product release from S1. Thus control operates at two distinct points in the docking process. The docking process itself is coupled to hydrolysis of ATP (the A-to-R isomerization is inhibited by the presence of the gamma Pi on ATP), and therefore all of these events are interrelated.The coming together of these different strands provides a biochemical framework that should allow the dynamic properties of the crossbridge in muscle to be understood.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-1403812, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-16386025, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-1824820, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-1825780, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-1845966, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-1871140, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-2009356, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-2276448, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-2322555, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-2528376, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-2760190, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-4091793, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-4713300, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-6219699, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-6237117, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-6715335, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-6871160, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-7918995, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-8107884, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-8218897, http://linkedlifedata.com/resource/pubmed/commentcorrection/7787067-8316858
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-3495
pubmed:author
pubmed:issnType
Print
pubmed:volume
68
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
194S-199S; discussion 199S-201S
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
The role of three-state docking of myosin S1 with actin in force generation.
pubmed:affiliation
Max Planck Institute for Molecular Physiology, Dortmund, Germany.
pubmed:publicationType
Journal Article, In Vitro, Review