Source:http://linkedlifedata.com/resource/pubmed/id/10820029
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
18
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| pubmed:dateCreated |
2000-7-6
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| pubmed:abstractText |
A myosin surface loop (amino acids 391-404) is postulated to be an important actin binding site. In human beta-cardiac myosin, mutation of arginine-403 to a glutamine or a tryptophan causes hypertrophic cardiomyopathy. There is a phosphorylatable serine or threonine residue present on this loop in some lower eukaryotic myosin class I and myosin class VI molecules. Phosphorylation of the myosin I molecules at this site regulates their enzymatic activity. In almost all other myosins, the homologous residue is either a glutamine or an aspartate, suggesting that a negative charge at this location is important for activity. To study the function of this loop, we have used site-directed mutagenesis and baculovirus expression of a heavy meromyosin- (HMM-) like fragment of human nonmuscle myosin IIA. An R393Q mutation (equivalent to the R403Q mutation in human beta-cardiac muscle myosin) has essentially no effect on the actin-activated MgATPase or in vitro motility of the expressed HMM-like fragment. Three mutations, D399K, D399A, and a deletion mutation that removes residues 393-402, all decrease both the V(max) of the actin-activated MgATPase by 8-10-fold and the rate of in vitro motility by a factor of 2-3. The K(ATPase) of the actin-activated MgATPase activity and the affinity constant for binding of HMM to actin in the presence of ADP are affected by less than a factor of 2. These data support an important role for the negative charge at this location but show that it is not critical to enzymatic activity.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Actins,
http://linkedlifedata.com/resource/pubmed/chemical/Ca(2 ) Mg(2 )-ATPase,
http://linkedlifedata.com/resource/pubmed/chemical/Molecular Motor Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Myosin Subfragments,
http://linkedlifedata.com/resource/pubmed/chemical/Myosins,
http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Proteins
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| pubmed:status |
MEDLINE
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| pubmed:month |
May
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| pubmed:issn |
0006-2960
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| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
9
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| pubmed:volume |
39
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
5555-60
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| pubmed:dateRevised |
2009-11-19
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| pubmed:meshHeading |
pubmed-meshheading:10820029-Actins,
pubmed-meshheading:10820029-Amino Acid Sequence,
pubmed-meshheading:10820029-Baculoviridae,
pubmed-meshheading:10820029-Ca(2+) Mg(2+)-ATPase,
pubmed-meshheading:10820029-Cardiomyopathy, Hypertrophic,
pubmed-meshheading:10820029-Humans,
pubmed-meshheading:10820029-Kinetics,
pubmed-meshheading:10820029-Models, Molecular,
pubmed-meshheading:10820029-Molecular Motor Proteins,
pubmed-meshheading:10820029-Molecular Sequence Data,
pubmed-meshheading:10820029-Mutagenesis, Site-Directed,
pubmed-meshheading:10820029-Mutation,
pubmed-meshheading:10820029-Myosin Subfragments,
pubmed-meshheading:10820029-Myosins,
pubmed-meshheading:10820029-Protein Binding,
pubmed-meshheading:10820029-Recombinant Proteins,
pubmed-meshheading:10820029-Sequence Alignment,
pubmed-meshheading:10820029-Static Electricity
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| pubmed:year |
2000
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| pubmed:articleTitle |
A conserved negatively charged amino acid modulates function in human nonmuscle myosin IIA.
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| pubmed:affiliation |
Laboratory of Molecular Cardiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1762, USA.
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| pubmed:publicationType |
Journal Article
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