Premium
Catalytic antibody light chain capable of cleaving a chemokine receptor CCR‐5 peptide with a high reaction rate constant
Author(s) -
Mitsuda Yukie,
Hifumi Emi,
Tsuruhata Kumi,
Fujinami Hiroko,
Yamamoto Naoki,
Uda Taizo
Publication year - 2004
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.20031
Subject(s) - immunoglobulin light chain , peptide , monoclonal antibody , chemistry , catalytic triad , antibody , peptide sequence , antigen , residue (chemistry) , amino acid , biochemistry , stereochemistry , microbiology and biotechnology , biology , gene , genetics , immunology
A monoclonal antibody (MAb), ECL2B‐2, was obtained by immunizing a peptide possessing a part of a sequence of a chemokine receptor, CCR‐5, which is present as a membrane protein on the macrophage surface, and which plays an important role in human immunodeficiency virus (HIV) infection. From the DNA and the deduced amino acid sequences of the light and heavy chains of ECL2B‐2 MAb, molecular modeling was conducted to calculate the steric conformation of the antibody. Modeling suggested that the structure of ECL2B‐2 could possess one or two catalytic triad(s), composed of Asp 1 , Ser 27a (or Ser 27e ), and His 93 (or His 27d ), in the light chain of ECL2B‐2. The three amino acid residues, Asp 1 , Ser 27a , and His 93 , are identical to those of catalytic antibody light chains such as VIPase and i41SL1‐2. The light chain of ECL2B‐2 MAb degraded the antigenic peptide CCR‐5 within about 100 h. Surprisingly, the light chain had a very high catalytic reaction rate constant ( k cat ) of 2.23 min −1 , which is greater by factors of tens to hundreds than those of natural catalytic antibodies obtained previously. The heavy chain of ECL2B‐2 MAb, which has no catalytic triad because of a lack of His residue, did not degrade the CCR‐5 peptide. © 2004 Wiley Periodicals, Inc.