Linked Life Data

6149574

Source:http://linkedlifedata.com/resource/pubmed/id/6149574

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1129
pubmed:dateCreated
1984-11-28
pubmed:abstractText
During activation of the first component of the classical complement pathway the two zymogen subcomponents, C1r and C1s are converted to active proteolytic enzymes. Activated C1r cleaves C1s which then becomes the activator of C4 and C2. Amino acid sequence studies of the proteolytic chains of C1r and C1s, carried out in Oxford and Aberdeen respectively, have shown that they belong to the serine proteinase family. Modelling of these sequences to the three-dimensional coordinates of chymotrypsin (Birktoft & Blow 1972) reveals that both molecules have a conserved structural core, and that most of the differences lie in the external loops. Catalytically functional residues (Ile-16, His-57, Asp-102, Ser-195) are conserved, and residue 189 is aspartic acid, consistent with the known trypsin-like specificity of cleavage. Examination of the amino acid sequences of C4a, and comparison with those of the homologous molecules C3a and C5a, shows that there is a marked difference in the distribution of basic residues near the C-terminal arginine residue which is the site of action of C1s. When these amino acid sequences are modelled to the coordinates of C3a (Huber et al. 1980) and docked to the active site of C1s, the basic residues of C4a appear to interact with two glutamate residues peculiar to C1s, suggesting that this interaction may contribute to the ability of C1s to discriminate C4 from C3 and C5.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0962-8436
pubmed:author
pubmed:issnType
Print
pubmed:day
6
pubmed:volume
306
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
293-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
Structure and activity of C1r and C1s.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't