Linked Life Data

8645007

Source:http://linkedlifedata.com/resource/pubmed/id/8645007

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1996-7-12
pubmed:abstractText
Selected physical and thermodynamic parameters for Escherichia coli alanyl-tRNA synthetase (AlaRS) have been determined primarily to assess the quaternary structure of this enzyme. The extinction coefficient (epsilon) at 280 nm was determined experimentally to be 0.71 ml mg-1 cm-1, and the partial specific volume (nu) was calculated from the amino acid composition to be 0.73 ml g-1. From viscosity experiments the intrinsic viscosity (eta) of AlaRS was extrapolated to be 3.4 ml g-1 and the degree of hydration (delta 1) estimated to be 0.67 gH2O g(-1)(AlaRS). Laser light-scattering studies indicated some heterogeneity; a radius of 6.3 nm was calculated for the major fraction with a diffusion coefficient (D20,W) of 3.89 x 10(-7) cm2 s-1. In 50 mM Hepes, pH 7.5, 20 mM KCl, 2 mM 2-mercaptoethanol and at a protein concentration of 4.2 mg ml-1 the sedimentation coefficient (S20,W) was 6.36 S; this value increased slightly when the protein concentration was decreased. The combination of S20,W and D20,W under these conditions yielded a molecular weight of approximately 186,000 Da, corresponding to a dimer. The S20,W was virtually independent of temperature in the range of 10-37 degrees C, while an Arrhenius plot of aminoacylation activity was biphasic. The isoelectric point was determined experimentally to be 4.9. Sedimentation equilibrium data were best fit to a decamer association complex in which dimeric AlaRS is the predominant species at 25 degrees C.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0003-9861
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
328
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
295-301
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Further characterization of Escherichia coli alanyl-tRNA synthetase.
pubmed:affiliation
Department of Biochemistry, Loma Linda University School of Medicine, California 92350-0001, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.