Linked Life Data

18006493

Source:http://linkedlifedata.com/resource/pubmed/id/18006493

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2008-1-21
pubmed:abstractText
Tropomyosin (Tm) is an alpha-helical coiled-coil actin-binding protein present in all eukaryotes from yeast to man. Its functional role has been best described in muscle regulation; however its much wider role in cytoskeletal actin regulation is still to be clarified. Isoforms vary in size from 284 or 248 amino acids in vertebrates, to 199 and 161 amino acids in yeast, spanning from 7 to 4 actin binding sites respectively. In Saccharomyces cerevisiae, the larger yTm1 protein is produced by an internal 38-amino acid duplication, corresponding to a single actin-binding site. We have produced an ultra-short Tm with only 125 amino acids by removing both of the 38 amino acid repeats from yTm1, with the addition of an Ala-Ser extension used to mimic the essential N-terminal acetylation. This short Tm, and an M1T mutant of it, bind to actin with a similar affinity to most Tms previously studied (K(50%) approximately 0.5 microm). However, an equilibrium fluorescence binding assay shows a much greater inhibition of myosin binding to actin than any previously studied Tm. Actin cosedimentation assays show this is caused by direct competition for binding to actin. The M1T mutant shows a reduced inhibition, probably due to weaker end-to-end interactions making it easier for myosin to displace Tm. All previously characterized Tms, although able to sterically block the myosin-binding site, are able to bind to actin along with myosin. By showing that Tm can compete directly with myosin for the same binding site these new Tms provide direct evidence for the steric blocking model.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
283
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1902-10
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Ultra short yeast tropomyosins show novel myosin regulation.
pubmed:affiliation
School of Biological and Chemical Sciences, Queen Mary, University of London, E1 4NS, United Kingdom. r.maytum@qmul.ac.uk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural