A mechanism-based probe for gp120-Hydrolyzing antibodies.
An antigenic peptide analogue consisting of HIV gp120 residues 421-431 (an antigen recognition site probe) with diphenyl amino(4-amidinophenyl)methanephosphonate located at the C-terminus (a catalytic site probe) was synthesized and its trypsin and antibody reactivity characteristics were studied. Antibodies to the peptide determinant recognized the peptidyl phosphonate probe. Trypsin was inhibited equipotently by the peptidyl phosphonate and its simple phosphonate counterpart devoid of the peptide determinant. The peptidyl phosphonate inhibited the gp120-hydrolyzing activity of a catalytic antibody light chain. It was bound covalently by the light chain and the binding was inhibited by the classical active-site directed inhibitor of serine proteinase, diisopropyl fluorophosphate. These results reveal that the peptidyl phosphonate ester can serve as a probe for the antigen recognition and catalytic subsites of proteolytic antibodies.
Taguchi
Hiroaki
H
Chemical Immunology and Therapeutics Research Center, Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, 6431 Fannin, Houston, TX 77030, USA.
Burr
Gary
G
Karle
Sangeeta
S
Planque
Stephanie
S
Zhou
Yong-Xin
YX
Paul
Sudhir
S
Nishiyama
Yasuhiro
Y
D000818:Animals; D000906:Antibodies / Q000737:chemistry*; D002384:Catalysis; D015195:Drug Design; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000276:immunology*; D006868:Hydrolysis; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology; D063065:Organophosphonates; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology; D012710:Serum Albumin, Bovine / Q000737:chemistry; D014357:Trypsin / Q000737:chemistry
D000906:Antibodies; D015699:HIV Envelope Protein gp120; D063065:Organophosphonates; D010455:Peptides; D015842:Serine Proteinase Inhibitors; D012710:Serum Albumin, Bovine; D010450:Endopeptidases; D014357:Trypsin