The crystal structure of the monoclinic form of L-histidine

Structure of 9-{2-[(4-imidazolyl)methylthio]ethyl}adenine

“…1 shows the conformation of the molecule with the atom numbering, bond distances and angles. The dimensions of the adenine moiety, the imidazolyl group and the linking part [from C(11) to C(6')] are in good agreement with those in the related compounds (Kistenmacher & Rossi, 1977;Takimoto, Takenaka & Sasada, 1981;Edington & Harding, 1974;Madden, McGrandy & Seeman, 1972;Prout, Critchley, Ganellin & Mitchell, 1977). The molecule is folded and the torsion angles N(9)-C(11)-C(12)-S, C(11)-C(12)-S-C(6') and C(12)-S-C(6')-C(5') are 60.1 (5), 87.8 (4) and -62.4 (4) °, respectively.…”

Investigation of the reactions of hexanitrocobaltate(III) with amino acids. XIII. The structure and absolute configuration of (–)589-ab-(histidinato-N,N')-cdf-(histidinato-O,N,N')-e-nitrocobalt(III) monohydrate

“…The most significant interaction exists between the N(3) atom from the imidazole ring of the tridentate histidine ligand and the 0(2') atom of the uncoordinated carboxylato group of the bidentate histidine in another adjacent complex molecule. Short N(imidazole)-O(carboxyl) distances are apparent in the structures of orthorhombic and monoclinic Lhistidine Madden, McGandy, Seeman, Harding & Hoy, 1972) and L-N-acetylhistidine (Kistenmacher, Hunt & Marsh, 1972). The N(3)--H(7)...O(2') hydrogen bond of 2.59 A is, to the best of our knowledge, one of the shortest hydrogen bonds of this type.…”

The crystal and molecular structure of L-N-acetylhistidine monohydrate: an application of direct methods to space group P1

“…In histidine itself Madden, McGandy, Seeman, Harding & Hoy, 1972) the a-amino nitrogen atom, N(1), is protonated rather than the imidazole ring; the acetyl group, which forms an amide linkage N(1)-C(7) with appreciable double-bond character, inhibits transfer of the proton to N(I) in the present compound. Both the imidazole ring and the c~-amino groups are protonated in histidine hydrochloride (Bennett, Davidson, Harding & Morelle, 1969;Donohue & Caron, 1964;Donohue, Lavine & Rollett, 1956).…”

“…In particular, histidine seems to be directly involved in the proteolysis mechanisms of the enzymes papain, subtilisin, chymotrypsin, trypsin, and other proteolytic enzymes, and in the coordination of zinc in zinc insulin (Tanford & Epstein, 1954) and zinc bacitracin (Craig, Philips & Burachik, 1969;Cornell & Gurney, 1970). Several X-ray diffraction studies involving the histidine moiety have now been reported: e-histidine hydrochloride (Donohue, Lavine & Rol[ett, 1956;Donohue & Caron, 1964), DL-histidine hydrochloride (Bennett, Davidson, Harding & Morelle, 1970), monoclinic g-histidine (Madden, McGandy, Seeman, Harding & Hoy, 1972), orthorhombic L-histidine , and several metal-histidine coordination complexes (see Freeman, 1967). One notable feature of these studies is that the histidine moiety occurs in two conformations -one 'open' and one 'closed' (Kistenmacher & Marsh, 1971); the magnitude of the torsion angle about the C(2)-C(3) (C'-C ~) bond differentiates between the two conformers.…”