Linked Life Data

17222909

Source:http://linkedlifedata.com/resource/pubmed/id/17222909

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2007-2-19
pubmed:abstractText
Antibodies (Abs) to the superantigenic determinant of HIV gp120 (gp120(SAg)) are potential protective agents against HIV infection. We report that the light chain subunits of Abs cloned from lupus patients using phage library methods bind and hydrolyze gp120(SAg) independent of the heavy chain. Unlike frequent gp120(SAg) recognition by intact Abs attributable to V(H) domain structural elements, the isolated light chains expressed this activity rarely. Four light chains capable of gp120(SAg) recognition were identified by fractionating phage displayed light chains using peptide probes containing gp120 residues 421-433, a gp120(SAg) component. Three light chains expressed non-covalent gp120(SAg) binding and one expressed gp120(SAg) hydrolyzing activity. The hydrolytic light chain was isolated by covalent phage fractionation using an electrophilic analog of residues 421-433. This light chain hydrolyzed a reporter gp120(SAg) substrate and full-length gp120. Other peptide substrates and proteins were hydrolyzed at lower rates or not at all. Consistent with the expected nucleophilic mechanism of hydrolysis, the light chain reacted selectively and covalently with the electrophilic gp120(SAg) peptide analog. The hydrolytic reaction entailed a fast initial step followed by a slower rate limiting step, suggesting rapid substrate acylation and slow deacylation. All four gp120(SAg)-recognizing light chains contained sequence diversifications relative to their germline gene counterparts. These observations indicate that in rare instances, the light chain subunit can bind and hydrolyze gp120(SAg) without the participation of the heavy chain. The pairing of such light chains with heavy chains capable of gp120(SAg) recognition represents a potential mechanism for generating protective Abs with enhanced HIV binding strength and anti-viral proteolytic activity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0161-5890
pubmed:author
pubmed:issnType
Print
pubmed:volume
44
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2707-18
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Antibodies to the superantigenic site of HIV-1 gp120: hydrolytic and binding activities of the light chain subunit.
pubmed:affiliation
Chemical Immunology and Therapeutics Research Center, Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, 6431 Fannin, Houston, TX 77030, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural