Open AccessAnalysis of Binding Sites for the New Small-Molecule CCR5 Antagonist TAK-220 on Human CCR5
Author(s) -
Masao Nishikawa,
Katsunori Takashima,
Toshiya Nishi,
Rie Furuta,
Naoyuki Kanzaki,
Yoshio Yamamoto,
Junichi Fujisawa
Publication year - 2005
Publication title -
antimicrobial agents and chemotherapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.07
H-Index - 259
eISSN - 1070-6283
pISSN - 0066-4804
DOI - 10.1128/aac.49.11.4708-4715.2005
Subject(s) - ccr5 receptor antagonist , small molecule , antagonist , receptor , amino acid , mutant , binding site , biology , transmembrane domain , plasma protein binding , conformational change , virus , chemistry , biochemistry , virology , chemokine receptor , chemokine , gene
G protein-coupled receptor CCR5 is the main coreceptor for macrophage-tropic human immunodeficiency virus type 1 (HIV-1), and various small-molecule CCR5 antagonists are being developed to treat HIV-1 infection. It has been reported that such CCR5 antagonists, including TAK-779, bind to a putative binding pocket formed by transmembrane domains (TMs) 1, 2, 3 and 7 of CCR5, indicating the importance of the conformational changes of the TMs during virus entry. In this report, using a single-round infection assay with human CCR5 and its substitution mutants, we demonstrated that a new CCR5 antagonist, TAK-220, shares the putative interacting amino acid residues Asn252 and Leu255 in TM6 with TAK-779 but also requires the distinct residues Gly163 and Ile198 in TMs 4 and 5, respectively, for its inhibitory effect. We suggested that, together with molecular models of the interactions between the drugs and CCR5, the inhibitory activity of TAK-220 could involve direct interactions with amino acid residues in TMs 4, 5, and 6 in addition to those in the previously postulated binding pocket. The possible interaction of drugs with additional regions of the CCR5 molecule would help to develop a new small-molecule CCR5 antagonist.