The crystal and molecular structure of streptomycin oxime selenate tetrahydrate

Abstract

The crystal and molecular structure and absolute configuration of the antibiotic streptomycin have been determined by an X-ray study of the hydrated oxime selenate. The compound (C 21 H 40 N 8 O 12 . 1 1/2 H 2 SeO 4 .4H 2 O) crystallizes in the monoclinic space group C 2, with cell dimensions a = 17.10(1), b = 14.36(1), c = 16.13(1)Å∥, β = 108.0(2)°; Z = 4 The structure was solved by the heavy-atom method, by using 3236 visually-estimated intensities, and refined to a conventional R of 0.086. The analysis has confirmed that streptomycin consists of three fragments, an N -methyl- α-L-glucosamine ring, an α-L-streptose and a streptidine ring, linked together by two glycosidic bonds. The crystal structure contains an elaborate network of hydrogen bonds linking selenate and streptomycin oxime ions and water molecules, analysis of which, though somewhat hampered by inability to observe the hydrogen atoms experimentally, reveals a disordered hydrogen bond occurring between two diad-related water molecules.