Catalytic antibody light chain capable of cleaving a chemokine receptor CCR-5 peptide with a high reaction rate constant
Catalytic antibody light chain capable of cleaving a chemokine receptor CCR-5 peptide with a high reaction rate constant
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DOI：
10.1002/bit.20031
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发表时间：
2004-04-20
影响因子：
3.8
通讯作者：
Uda, T
中科院分区：
文献类型：
--
作者：
Mitsuda, Y;Hifumi, E;Uda, T
通过免疫具有趋化因子受体CCR-5的部分序列的肽获得单克隆抗体（MAb）ECL 2B-2，所述趋化因子受体CCR-5作为膜蛋白存在于巨噬细胞表面上，并且在人类免疫缺陷病毒（HIV）感染中起重要作用。根据ECL 2B-2单抗轻链和重链的DNA和推导的氨基酸序列，进行分子建模以计算抗体的空间构象。建模表明，在ECL 2B-2的轻链中，ECL 2B-2的结构可能具有一个或两个催化三联体，由Asp（1）、Ser（27 a）（或Ser（27 e））和His（93）（或His（27 d））组成。三个氨基酸残基Asp '、Ser和His与催化性抗体轻链如VIPase和i41 SL 1 -2的那些相同。ECL 2B-2单抗轻链在100 h内降解抗原肽CCR-5。令人惊讶的是，轻链具有非常高的催化反应速率常数（k（cat）），为2.23 min（-1），其比先前获得的天然催化抗体的催化反应速率常数大数十至数百倍。由于缺少His残基而不具有催化三联体的ECL 2B-2 MAb的重链不降解CCR-5肽。(C)2004 Wiley Periodicals，Inc.
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', Ser, and His, are identical to those of catalytic antibody light chains such as VIPase and i41 SL1-2. 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. (C) 2004 Wiley Periodicals, Inc.