X-ray crystallographic structure and absolute configuration of the cyclic Di-amino acid peptide: cyclo(l-HomoCySH-l-HomoCySH)
X-ray crystallographic structure and absolute configuration of the cyclic Di-amino acid peptide: cyclo(l-HomoCySH-l-HomoCySH)
The cyclic di-amino acid peptide cyclo(l-homoCySH-l-homoCySH) [(3S, 6S)-3, 6-bis(2-sulfanylethyl) piperazine-2,5-dione, C8H14N2O2S2, crystallizes in the orthorhombic space group P2(1)2(1)2(1) with unit cell parameters a = 6.1509(2) , b = 18.0217(9) , c = 29.6166(14) , V = 3283.0(2) (3), Z = 12 (3 molecules, A, B and C, per asymmetric unit), D (c) = 1.422 g cm(-3) and a linear absorption coefficient of 0.464 mm(-1). The crystal structure determination was carried out with MoK alpha X-ray data measured at 120(2) K. In the final refinement cycle the data/restraints/parameter ratios were 5595/0/385 and goodness-of-fit on F (2) = 1.084. Final R indices for [I > 2sigma(I)] were R1 = 0.0746, wR2 = 0.1356 and R indices (all data) R1 = 0.1092, wR2 = 0.1529. The largest electron density difference peak and hole were 0.526 and -0.445e (-3). The DKP rings in all three molecules are essentially, and unusually, planar and the C=O oxygen atoms are co-planar with the ring in each case. Ring atom rms deviations, including the =O groups, are 0.0668, 0.0658 and 0.0656 in molecules A, B and C, respectively. Details of the molecular geometry are compared with the compound cyclo(Gly-Gly) (Degeilh R, Marsh RE Acta Cryst 12:1007, 1959) and in addition some cyclic di-amino acid peptides in which the DKP rings have more puckered boat conformations.
1328-1334
Mendham, Andrew P.
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Spencer, John
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Chowdhry, Babur Z.
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Dines, Trevor J.
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Mujahid, Muhammad
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Palmer, Rex A.
f5531d86-e004-43ea-bce3-515f98d6e329
Tizzard, Graham J.
8474c0fa-40df-43a6-a662-7f3c4722dbf2
Coles, Simon J.
3116f58b-c30c-48cf-bdd5-397d1c1fecf8
September 2011
Mendham, Andrew P.
899f3396-7a41-462e-a4a0-4721877db064
Spencer, John
a3cf55cd-a4c7-4af6-b16c-96c8fb8c4cf4
Chowdhry, Babur Z.
23ca9320-2960-46f0-adb9-6fb6a995bfaf
Dines, Trevor J.
c41e31fe-2d3e-45a4-a117-e1b4c8e67c63
Mujahid, Muhammad
8a59ab14-9132-4ae2-8769-404a7c9bf517
Palmer, Rex A.
f5531d86-e004-43ea-bce3-515f98d6e329
Tizzard, Graham J.
8474c0fa-40df-43a6-a662-7f3c4722dbf2
Coles, Simon J.
3116f58b-c30c-48cf-bdd5-397d1c1fecf8
Mendham, Andrew P., Spencer, John, Chowdhry, Babur Z., Dines, Trevor J., Mujahid, Muhammad, Palmer, Rex A., Tizzard, Graham J. and Coles, Simon J.
(2011)
X-ray crystallographic structure and absolute configuration of the cyclic Di-amino acid peptide: cyclo(l-HomoCySH-l-HomoCySH).
Journal of Chemical Crystallography, 41 (9), .
(doi:10.1007/s10870-011-0098-3).
Abstract
The cyclic di-amino acid peptide cyclo(l-homoCySH-l-homoCySH) [(3S, 6S)-3, 6-bis(2-sulfanylethyl) piperazine-2,5-dione, C8H14N2O2S2, crystallizes in the orthorhombic space group P2(1)2(1)2(1) with unit cell parameters a = 6.1509(2) , b = 18.0217(9) , c = 29.6166(14) , V = 3283.0(2) (3), Z = 12 (3 molecules, A, B and C, per asymmetric unit), D (c) = 1.422 g cm(-3) and a linear absorption coefficient of 0.464 mm(-1). The crystal structure determination was carried out with MoK alpha X-ray data measured at 120(2) K. In the final refinement cycle the data/restraints/parameter ratios were 5595/0/385 and goodness-of-fit on F (2) = 1.084. Final R indices for [I > 2sigma(I)] were R1 = 0.0746, wR2 = 0.1356 and R indices (all data) R1 = 0.1092, wR2 = 0.1529. The largest electron density difference peak and hole were 0.526 and -0.445e (-3). The DKP rings in all three molecules are essentially, and unusually, planar and the C=O oxygen atoms are co-planar with the ring in each case. Ring atom rms deviations, including the =O groups, are 0.0668, 0.0658 and 0.0656 in molecules A, B and C, respectively. Details of the molecular geometry are compared with the compound cyclo(Gly-Gly) (Degeilh R, Marsh RE Acta Cryst 12:1007, 1959) and in addition some cyclic di-amino acid peptides in which the DKP rings have more puckered boat conformations.
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Published date: September 2011
Organisations:
Organic Chemistry: Synthesis, Catalysis and Flow
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Local EPrints ID: 346174
URI: http://eprints.soton.ac.uk/id/eprint/346174
ISSN: 1074-1542
PURE UUID: d3dba786-8e7c-4188-95b7-7cd77efaeb30
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Date deposited: 18 Dec 2012 11:40
Last modified: 15 Mar 2024 03:10
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Author:
Andrew P. Mendham
Author:
John Spencer
Author:
Babur Z. Chowdhry
Author:
Trevor J. Dines
Author:
Muhammad Mujahid
Author:
Rex A. Palmer
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