Nucleotide–amino acid interactions in theL-His–IMP·MeOH·H2O complex

Abstract

In the crystal structure of the methanol-solvated monohydrated complex of L-histidine (His) with inosine 5'-monophosphate (IMP), namely L-histidinium inosine-5'-phosphate methanol solvate monohydrate, C(6)H(10)N(3)O(2)(+).C(10)H(12)N(4)O(8)P(-).CH(3)OH.H(2)O, most of the interactions between IMP anions (anti/C3'-endo/gauche-gauche conformers) are realized between the riboses and hypoxanthine bases in a trans sugar-edge/sugar-edge geometry, and between the phosphate groups. The base Watson-Crick edge is involved in additional methanol-mediated IMP...MeOH...IMP contacts. Specific and nonspecific nucleotide-amino acid (IMP...His) interactions engage the Hoogsteen edges of the base and phosphate group, respectively. Additional stabilization of His...IMP contacts is provided by pi-pi stacking between the imidazolium ring of His and the hypoxanthine base of IMP. The results may indicate the possible recognition mechanism between His and IMP.