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dc.contributor.authorZhao, Fa-Qing
dc.contributor.authorCraig, Roger W.
dc.date2022-08-11T08:09:38.000
dc.date.accessioned2022-08-23T16:38:32Z
dc.date.available2022-08-23T16:38:32Z
dc.date.issued2008-07-01
dc.date.submitted2009-11-30
dc.identifier.citation<p>J Mol Biol. 2008 Aug 29;381(2):256-60. Epub 2008 Jun 18. <a href="http://dx.doi.org/10.1016/j.jmb.2008.06.032">Link to article on publisher's site</a></p>
dc.identifier.issn1089-8638 (Electronic)
dc.identifier.doi10.1016/j.jmb.2008.06.032
dc.identifier.pmid18585394
dc.identifier.urihttp://hdl.handle.net/20.500.14038/39271
dc.description.abstractContraction of many muscles is activated in part by the binding of Ca(2+) to, or phosphorylation of, the myosin heads on the surface of the thick filaments. In relaxed muscle, the myosin heads are helically ordered and undergo minimal interaction with actin. On Ca(2+) binding or phosphorylation, the head array becomes disordered, reflecting breakage of the head-head and other interactions that underlie the ordered structure. Loosening of the heads from the filament surface enables them to interact with actin filaments, bringing about contraction. On relaxation, the heads return to their ordered positions on the filament backbone. In scallop striated adductor muscle, the disordering that takes place on Ca(2+) binding occurs on the millisecond time scale, suggesting that it is a key element of muscle activation. Here we have studied the reverse process. Using time-resolved negative staining electron microscopy, we show that the rate of reordering on removal of Ca(2+) also occurs on the same physiological time scale. Direct observation of images together with analysis of their Fourier transforms shows that activated heads regain their axial ordering within 20 ms and become ordered in their final helical positions within 50 ms. This rapid reordering suggests that reformation of the ordered structure, and the head-head and other interactions that underlie it, is a critical element of the relaxation process.
dc.language.isoen_US
dc.relation<p><a href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&list_uids=18585394&dopt=Abstract">Link to Article in PubMed</a></p>
dc.relation.urlhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC2527059/
dc.subjectAnimals
dc.subjectCalcium
dc.subjectCryoelectron Microscopy
dc.subjectKinetics
dc.subjectMicrofilaments
dc.subjectMollusca
dc.subjectMyosins
dc.subjectTime Factors
dc.subjectLife Sciences
dc.subjectMedicine and Health Sciences
dc.titleMillisecond time-resolved changes occurring in Ca2+-regulated myosin filaments upon relaxation
dc.typeJournal Article
dc.source.journaltitleJournal of molecular biology
dc.source.volume381
dc.source.issue2
dc.identifier.legacycoverpagehttps://escholarship.umassmed.edu/oapubs/2072
dc.identifier.contextkey1074371
html.description.abstract<p>Contraction of many muscles is activated in part by the binding of Ca(2+) to, or phosphorylation of, the myosin heads on the surface of the thick filaments. In relaxed muscle, the myosin heads are helically ordered and undergo minimal interaction with actin. On Ca(2+) binding or phosphorylation, the head array becomes disordered, reflecting breakage of the head-head and other interactions that underlie the ordered structure. Loosening of the heads from the filament surface enables them to interact with actin filaments, bringing about contraction. On relaxation, the heads return to their ordered positions on the filament backbone. In scallop striated adductor muscle, the disordering that takes place on Ca(2+) binding occurs on the millisecond time scale, suggesting that it is a key element of muscle activation. Here we have studied the reverse process. Using time-resolved negative staining electron microscopy, we show that the rate of reordering on removal of Ca(2+) also occurs on the same physiological time scale. Direct observation of images together with analysis of their Fourier transforms shows that activated heads regain their axial ordering within 20 ms and become ordered in their final helical positions within 50 ms. This rapid reordering suggests that reformation of the ordered structure, and the head-head and other interactions that underlie it, is a critical element of the relaxation process.</p>
dc.identifier.submissionpathoapubs/2072
dc.contributor.departmentDepartment of Cell Biology
dc.source.pages256-60


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