Linked Life Data

15383587

Source:http://linkedlifedata.com/resource/pubmed/id/15383587

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
2004-9-22
pubmed:abstractText
Studies reported over 30 years ago revealed that latent, nonactivated C5 binds specifically and reversibly to C6 and C7. These reversible reactions are distinct from the essentially nonreversible associations with activated C5b that occur during assembly of the membrane attack complex, but they likely involve some, perhaps many, of the same molecular contacts. We recently reported that these reversible reactions are mediated by the C345C (NTR) domain at the C terminus of the C5 alpha-chain. Earlier work by others localized the complementary binding sites to a tryptic fragment of C6 composed entirely of two adjacent factor I modules (FIMs), and to a larger fragment of C7 composed of its homologous FIMs as well as two adjoining short consensus repeat modules. In this work, we expressed the tandem FIMs from C7 in bacteria. The mobility on SDS-polyacrylamide gels, lack of free sulfhydryl groups, and atypical circular dichroism spectrum of the recombinant product rC7-FIMs were all consistent with a native structure. Using surface plasmon resonance, we found that rC7-FIMs binds specifically to both C5 and the rC5-C345C domain with K(D) approximately 50 nM, and competes with C7 for binding to C5, as expected for an active domain. These results indicate that, like C6, the FIMs alone in C7 mediate reversible binding to C5. Based on available evidence, we suggest a model for an irreversible membrane attack complex assembly in which the C7 FIMs, but not those in C6, are bound to the C345C domain of C5 within the fully assembled complex.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
173
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4547-52
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:15383587-Amino Acid Motifs, pubmed-meshheading:15383587-Circular Dichroism, pubmed-meshheading:15383587-Complement C3, pubmed-meshheading:15383587-Complement C5, pubmed-meshheading:15383587-Complement C6, pubmed-meshheading:15383587-Complement C7, pubmed-meshheading:15383587-Complement Factor I, pubmed-meshheading:15383587-Complement Membrane Attack Complex, pubmed-meshheading:15383587-Disulfides, pubmed-meshheading:15383587-Escherichia coli, pubmed-meshheading:15383587-Humans, pubmed-meshheading:15383587-Oxidation-Reduction, pubmed-meshheading:15383587-Protein Binding, pubmed-meshheading:15383587-Protein Structure, Tertiary, pubmed-meshheading:15383587-Protein Subunits, pubmed-meshheading:15383587-Receptors, Cell Surface, pubmed-meshheading:15383587-Recombinant Proteins, pubmed-meshheading:15383587-Surface Plasmon Resonance
pubmed:year
2004
pubmed:articleTitle
Complement components C5 and C7: recombinant factor I modules of C7 bind to the C345C domain of C5.
pubmed:affiliation
Torrey Pines Institute for Molecular Studies, San Diego, CA 92121, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.