226
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Srikrishnan T, Parthasarathy R. A novel intercalation of a water molecule between pyrimidine bases in 5-nitro-1-(β-D-ribosyluronic acid)–uracil monohydrate [1-(5-nitro-2,4-dioxopyrimidinyl)-β-D-ribofuranuronic acid monohydrate]. ACTA ACUST UNITED AC 1978. [DOI: 10.1107/s0567740878005609] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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227
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Chen CS, Srikrishnan T, Parthasarathy R. Conformation of L-cystathionine, a carba analog of cystine, and stereochemistry of hormone-receptor interactions. Biochim Biophys Acta Gen Subj 1978; 538:534-40. [PMID: 203329 DOI: 10.1016/0304-4165(78)90414-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The conformation of L-cystathionine, a carba analog of L-cystine, has been studied in the solid state using X-ray diffraction techniques. Crystal of L-cystathionine are tetragonal, space group P41 with cell constants a = 6.691(1) A, c = 21.998(3) A and Z = 4. From diffractometer data to the limit of 2theta = 162 degrees for Cukalpha, the structure was refined using full-matrix least-squares to an R value of 0.061. L-Cystathionine is isostructural chemically to L-cystine and its crystal structure is isomorphous to tetragonal L-cystine (Chaney, M.O. and Steinrauf, L.K. (1974) Acta Crystallogr. 1330, 711--716). The crystal structure of L-cystathionine is disordered, leading to two slightly differing conformers of L-cystathionine (each with half occupancy) with same helical sense but running in opposite directions and occupying the locations of L-cystine molecules in tetragonal L-cystine structure. Their conformational similarity, even when no sterical constraints such as cyclization are present, offers an explanation of the activities of the carba analogs of neuro-hypophysial hormones in terms of the structural integrity of the disulfide-like bridges.
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228
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Soriano-Garcia M, Parthasarathy R. A short intramolecular hydrogen bond in the structure of the superacid salt lithium trihydrogen dimalonate. ACTA ACUST UNITED AC 1978. [DOI: 10.1039/p29780000668] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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229
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Chen CS, Parthasarathy R. Specific configurations of hydrogen bonding. I. Hydrogen bonding and conformational preferences of N-acylamino-acids, peptides and derivatives. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1978; 11:9-18. [PMID: 631990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
From a reexamination of the X-ray studies of the crystal structures of 27 N-acylamino acids, peptides and their derivatives and 30 linear peptides, it is concluded that specific formation of short intermolecular hydrogen bonds (2,5 to 2.6 A) from the carboxyl OH to the N-acyl oxygen is an important feature for N-acylamino acids. For N-acyl-N-amides, the formation of hydrogen bonds 2.7 to 2.9A long between N(acyl-H...O(amide) is strongly preferred. The dihedral angle delta between the N-acyl and carboxyl groups or adjacent amide groups shows a preference for values near 20 degrees or 90 degrees for N-acylamino acids and 90 degrees for N-acyl-N-amides.
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Parthasarathy R, Ohrt JM, Chheda GB. Modified nucleosides and conformation of anticodon loops: crystal structure of t6A and g6A. Biochemistry 1977; 16:4999-5008. [PMID: 911810 DOI: 10.1021/bi00642a010] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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231
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Chen CS, Parthasarathy R. Structure and conformation of amino acids containing sulfur. V. N-Formyl-L-methionine. ACTA ACUST UNITED AC 1977. [DOI: 10.1107/s0567740877010942] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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232
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Soriano-Garcia M, Parthasarathy R. Stereochemistry and hydrogen bonding of cytokinins: 6-furfurylaminopurine (kinetin). ACTA ACUST UNITED AC 1977. [DOI: 10.1107/s0567740877009194] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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233
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Parthasarathy R, Srikrishnan T. A new pattern of hydrogen bonding between perpendicular bases in the crystal structure of 5-nitro-6-methyluracil. ACTA CRYSTALLOGRAPHICA SECTION B: STRUCTURAL SCIENCE 1977. [DOI: 10.1107/s0567740877007006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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234
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Kou WWH, Parthasarathy R. 6-Methyl-5,6-dihydrouracil, a highly disordered structure. ACTA ACUST UNITED AC 1977. [DOI: 10.1107/s0567740877005068] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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235
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Nazareth O, Parthasarathy R, Ramakrishnan CV, Santha T, Sivasubramanian SS, Somasundaram PR, Subbammal S, Tripathy SP. Efficacy of once-weekly isoniazid-streptomycin in preventing relapse of pulmonary tuberculosis. Indian J Med Res 1977; 65:35-42. [PMID: 324906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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236
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237
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Srikrishnan T, Parthasarathy R. "Sandwiched" water molecule between pyrimidine bases and intra-molecular C-H ... Q hydrogen bonding in 5-nitro-1-(beta-D-ribosyluronic acid)-uracil monohydrate. Nature 1976; 264:379-80. [PMID: 1004565 DOI: 10.1038/264379a0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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238
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Parthasarathy R, Ohrt JM, Chheda GB. Structure and stereochemistry of nucleic acid components and their reaction products. IV. Crystal structure of the potassium salt of N-(purin-6-ylcarbamoyl)glycine monohydrate. ACTA ACUST UNITED AC 1976. [DOI: 10.1107/s0567740876008431] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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239
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Chen CS, Parthasarathy R, De Titta GT. Crystal and molecular structure of d, l-dethiobiotin. Role of sulfur in biotin stereochemistry. J Am Chem Soc 1976; 98:4983-90. [PMID: 950421 DOI: 10.1021/ja00432a045] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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240
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Parthasarathy R, Devadatta S, Fox W, Krishnaswami KV, Radhakrishna S, Somasundaram PR, Tripathy SP. Studies of immediate adverse reactions to different doses of a slow-release preparation of isoniazid. TUBERCLE 1976; 57:115-21. [PMID: 785735 DOI: 10.1016/0041-3879(76)90048-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
'Double-blind' studies were carried out to assess the incidence of immediate adverse reactions to different doses of a slow-release preparation of isoniazid (matrix isoniazid). Individual doses of 30 mg/kg matrix isoniazid were well-tolerated but higher doses resulted in giddiness, the incidence being dose-related. The giddiness was characterized by a late onset and was usually present even at 24 hours. A few patients complained of gastro-intestinal symptoms. It is concluded that matrix isoniazid can be given to Madras patients in doses of 30-40 mg/kg without risk of an undue incidence of immediate adverse reactions.
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241
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Parthasarathy R, Soriano-Garcia M, Chheda GB. Bifurcated hydrogen bonds and flip--flop conformation in a modified nucleic acid base, gc6 Ade. Nature 1976; 260:807-8. [PMID: 4737 DOI: 10.1038/260807a0] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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242
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Ramakrishnan CV, Parthasarathy R, Sambamoorthy S, Somasundaram PR, Subbammal S. Cycloserine plus ethionamide plus pyrazinamide in the treatment of patients excreting isoniazid-resistant tubercle bacilli following previous chemotherapy. Indian J Med Res 1976; 64:76-82. [PMID: 818010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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243
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Bobek M, Bloch A, Parthasarathy R, Whistler RL. Synthesis and biological activity of 5-fluoro-4'-thiouridine and some related nucleosides. J Med Chem 1975; 18:784-7. [PMID: 808609 DOI: 10.1021/jm00242a004] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The synthesis of a series of 4'-thio-5-halogenopyrimidine nucleosides, including the 5-fluoro, chloro, bromo and iodo derivatives, has been carried out by condensation of the 2,4-bis-O-trimethylsilyl derivatives of the corresponding pyrimidine bases with the protected 4-thio-D-ribofuranosyl chloride. Among these, the alpha and beta anomers of 4'-thio-5-fluorouridine inhibited the growth of leukemia L1210 cells at concentrations of 4 x 10(-7) and 2 x 10(-7) M, respectively, and that of S. faecium at 4 x 10(-9) and 6 x 10(-10) M, respectively. These compounds retained marked activity against strains of S. faecium resistant to 10(-3) M 5-fluorouracil or 5-fluorouridine. As determined in S. faecium cultures, 4'-thio-5-fluorouridine decreased the total protein content of the cells more markedly than it did their RNA or DNA content. X-Ray crystallography showed that substitution of sulfur for the oxygen in the carbohydrate ring markedly changes the conformation of that moiety.
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244
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Rosenfield RE, Parthasarathy R. Structure and conformation of amino acids containing sulfur. IV. The crystal structure of L-cystine dihydrobromide dihydrate: a novel conformation. ACTA ACUST UNITED AC 1975. [DOI: 10.1107/s0567740875003858] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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245
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Rosenfield RE, Parthasarathy R. Structure and conformation of amino acids containing sulfur. III. The crystal structure and absolute configuration of 3,3,3',3'-tetramethyl-D-cystine (D-penicillamine disulfide) dihydrochloride: an unusually short intramolecular N–H...S contact distance. ACTA ACUST UNITED AC 1975. [DOI: 10.1107/s0567740875003020] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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246
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Soriano-Garcia M, Parthasarathy R. Structure-activity relationship of cytokinins: crystal structure and conformation of 6-furfurylaminopurine (kinetin). Biochem Biophys Res Commun 1975; 64:1062-8. [PMID: 1147957 DOI: 10.1016/0006-291x(75)90155-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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247
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Parthasarathy R, Ohrt JM, Chheda GB. Structure and stereochemistry of nucleic acid components and their reaction products. III. Crystal structure of the potassium salt of N-(purin-6-ylcarbamoyl)-L-threonine. Possible role of hypermodified bases adjacent to anticodon in codon-anticodon interaction. J Am Chem Soc 1974; 96:8087-94. [PMID: 4464320 DOI: 10.1021/ja00833a039] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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248
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Parthasarathy R, Ohrt JM, Chheda GB. Conformation and possible role of hypermodified nucleosides adjacent to 3'-end of anticodon in tRNA: N-(purin-6-ylcarbamoyl)-L-threonine riboside. Biochem Biophys Res Commun 1974; 60:211-8. [PMID: 4423161 DOI: 10.1016/0006-291x(74)90193-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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249
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Parthasarathy R, Ohrt JM, Chheda GB. Conformation of N-(purin-6ylcarbamoyl) glycine, a hypermodified base in tRNA. Biochem Biophys Res Commun 1974; 57:649-53. [PMID: 4827827 DOI: 10.1016/0006-291x(74)90595-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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250
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Rosenfield RE, Parthasarathy R. Structure and conformation of amino acids containing sulfur. II. The crystal of meso-lanthionine dihydrochloride; a short intermolecular S--S contact distance. J Am Chem Soc 1974; 96:1925-30. [PMID: 4815762 DOI: 10.1021/ja00813a045] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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