Linked Life Data

10809750

Source:http://linkedlifedata.com/resource/pubmed/id/10809750

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
2000-6-21
pubmed:abstractText
Actin-activated MgATPase of smooth muscle heavy meromyosin is activated by thiophosphorylation of two regulatory light chains, one on each head domain. To understand cooperativity between heads, we examined the kinetics of heavy meromyosin (HMM) with one thiophosphorylated head. Proteolytic gizzard heavy meromyosin regulatory light chains were partially exchanged with recombinant thiophosphorylated His-tagged light chains, and HMM with one thiophosphorylated head was isolated by nickel-affinity chromatography. In vitro motility was observed. By steady-state kinetic analysis, one-head thiophosphorylated heavy meromyosin had a similar K(m) value for actin but a V(max) value of approximately 50% of the fully thiophosphorylated molecule. However, single turnover analysis, which is not sensitive to small amounts of active heads, showed that one-head thiophosphorylated heavy meromyosin was 46-120 times more active than unphosphorylated HMM but only 7-19% as active as the fully thiophosphorylated molecule. Discrepancy between the single turnover and steady-state values could be explained by a small fraction of rigor heads. These rigor heads would have a large effect on the steady-state kinetics of one-head thiophosphorylated HMM. In summary, thiophosphorylation of one head leads to a molecule with unique intermediate kinetics suggesting that thiophosphorylation of one head cooperatively alters the kinetics of the partner head and vice versa.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15142-51
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2000
pubmed:articleTitle
Kinetics of smooth muscle heavy meromyosin with one thiophosphorylated head.
pubmed:affiliation
Department of Biochemistry, the University of Nevada, Reno, Nevada 89557, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't