TY - JOUR

T1 - Metal ion enhanced binding of AMD3100 to Asp262 in the CXCR4 receptor

AU - Gerlach, Lars Ole

AU - Jakobsen, Janus S

AU - Jensen, Kasper P

AU - Rosenkilde, Mette R

AU - Skerlj, Renato T

AU - Ryde, Ulf

AU - Bridger, Gary J

AU - Schwartz, Thue W

N1 - Keywords: Amino Acid Sequence; Animals; Aspartic Acid; Binding, Competitive; COS Cells; Carboxylic Acids; Cations, Divalent; Chemokine CXCL12; Chemokines, CXC; Copper; DNA Mutational Analysis; Heterocyclic Compounds; Humans; Ligands; Macromolecular Substances; Metals, Heavy; Molecular Sequence Data; Mutagenesis, Site-Directed; Nickel; Receptors, CXCR4; Transfection; Zinc

PY - 2003

Y1 - 2003

N2 - The affinity of AMD3100, a symmetrical nonpeptide antagonist composed of two 1,4,8,11-tetraazacyclotetradecane (cyclam) rings connected through a 1,4-dimethylene(phenylene) linker to the CXCR4 chemokine receptor was increased 7, 36, and 50-fold, respectively, by incorporation of the following: Cu(2+), Zn(2+), or Ni(2+) into the cyclam rings of the compound. The rank order of the transition metal ions correlated with the calculated binding energy between free acetate and the metal ions coordinated in a cyclam ring. Construction of AMD3100 substituted with only a single Cu(2+) or Ni(2+) ion demonstrated that the increase in binding affinity of the metal ion substituted bicyclam is achieved through an enhanced interaction of just one of the ring systems. Mutational analysis of potential metal ion binding residues in the main ligand binding crevice of the CXCR4 receptor showed that although binding of the bicyclam is dependent on both Asp(171) and Asp(262), the enhancing effect of the metal ion was selectively eliminated by substitution of Asp(262) located at the extracellular end of TM-VI. It is concluded that the increased binding affinity of the metal ion substituted AMD3100 is obtained through enhanced interaction of one of the cyclam ring systems with the carboxylate group of Asp(262). It is suggested that this occurs through a strong concomitant interaction of one of the oxygen's directly with the metal ion and the other oxygen to one of the nitrogens of the cyclam ring through a hydrogen bond.

AB - The affinity of AMD3100, a symmetrical nonpeptide antagonist composed of two 1,4,8,11-tetraazacyclotetradecane (cyclam) rings connected through a 1,4-dimethylene(phenylene) linker to the CXCR4 chemokine receptor was increased 7, 36, and 50-fold, respectively, by incorporation of the following: Cu(2+), Zn(2+), or Ni(2+) into the cyclam rings of the compound. The rank order of the transition metal ions correlated with the calculated binding energy between free acetate and the metal ions coordinated in a cyclam ring. Construction of AMD3100 substituted with only a single Cu(2+) or Ni(2+) ion demonstrated that the increase in binding affinity of the metal ion substituted bicyclam is achieved through an enhanced interaction of just one of the ring systems. Mutational analysis of potential metal ion binding residues in the main ligand binding crevice of the CXCR4 receptor showed that although binding of the bicyclam is dependent on both Asp(171) and Asp(262), the enhancing effect of the metal ion was selectively eliminated by substitution of Asp(262) located at the extracellular end of TM-VI. It is concluded that the increased binding affinity of the metal ion substituted AMD3100 is obtained through enhanced interaction of one of the cyclam ring systems with the carboxylate group of Asp(262). It is suggested that this occurs through a strong concomitant interaction of one of the oxygen's directly with the metal ion and the other oxygen to one of the nitrogens of the cyclam ring through a hydrogen bond.

U2 - 10.1021/bi0264770

DO - 10.1021/bi0264770

M3 - Journal article

C2 - 12534283

VL - 42

SP - 710

EP - 717

JO - Biochemistry

JF - Biochemistry

SN - 0006-2960

IS - 3

ER -