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. 1981 Feb;78(2):681–685. doi: 10.1073/pnas.78.2.681

Conformation of cyclo(Gly-L-Pro-L-Pro-Gly-L-Pro-L-Pro)2Mg2+ complex crystallized from C2H3CN solution

Isabella L Karle 1, Jerome Karle 1
PMCID: PMC319863  PMID: 16592971

Abstract

The cyclic hexapeptides (Gly-L-Pro-L-Pro-Gly-L-Pro-L-Pro) in the (peptide—Mg—peptide)2+ complex have nearly identical asymmetric conformations. Each has two cis Pro-Pro linkages and lacks any intraring hydrogen bonds. The Mg2+ ion forms six ligands in a regular octahedral array with the carbonyl oxygen atoms of the two Gly residues and one Pro residue of each peptide. The “sandwich” complex has an approximate 2-fold rotation axis through the Mg2+ relating the two peptide moieties. Cyclo(Gly-Pro-Pro-Gly-Pro-Pro)2Mg(ClO4)2· 4C2H3CN crystallizes in space group P31 with a = b = 15.744(4) Å, c = 24.002(6) Å, γ = 120°, and Z = 3. A highlight of the structure determination is the ready location of the Mg self-vector in a Harker section and the development of the entire structure by use of the tangent formula starting with the known position of the Mg atom.

Keywords: x-ray analysis, magnesium—oxygen ligands, sandwich complex, solvent channels, tangent formula

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Chiu Y. Y., Brown L. D., Lipscomb W. N. Crystal and molecular structure of complex between cyclo(L-prolylglycyl)4 and RbSCN. J Am Chem Soc. 1977 Jul 6;99(14):4799–4803. doi: 10.1021/ja00456a043. [DOI] [PubMed] [Google Scholar]
  2. Hamilton J. A., Steinrauf L. K., Braden B. Beauvericin and divalent cations: crystal structure of the barium complex. Biochem Biophys Res Commun. 1975 May 5;64(1):151–156. doi: 10.1016/0006-291x(75)90231-4. [DOI] [PubMed] [Google Scholar]
  3. Karle I. L., Karle J., Wieland T., Burgermeister W., Faulstich H., Witkop B. Conformations of the li-antamanide complex and na-[phe, val]antamanide complex in the crystalline state. Proc Natl Acad Sci U S A. 1973 Jun;70(6):1836–1840. doi: 10.1073/pnas.70.6.1836. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Karle I. L., Wieland T., Schermer D., Ottenheym H. C. Conformation of uncomplexed natural antamanide crystallized from CH(3)CN/H(2)O. Proc Natl Acad Sci U S A. 1979 Apr;76(4):1532–1536. doi: 10.1073/pnas.76.4.1532. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Neupert-Laves K., Dobler M. The crystal structure of a K+ complex of valinomycin. Helv Chim Acta. 1975 Mar 12;58(2):432–442. doi: 10.1002/hlca.19750580212. [DOI] [PubMed] [Google Scholar]
  6. Pinkerton M., Steinrauf L. K., Dawkins P. The molecular structure and some transport properties of valinomycin. Biochem Biophys Res Commun. 1969 May 22;35(4):512–518. doi: 10.1016/0006-291x(69)90376-3. [DOI] [PubMed] [Google Scholar]
  7. Quigley G. J., Teeter M. M., Rich A. Structural analysis of spermine and magnesium ion binding to yeast phenylalanine transfer RNA. Proc Natl Acad Sci U S A. 1978 Jan;75(1):64–68. doi: 10.1073/pnas.75.1.64. [DOI] [PMC free article] [PubMed] [Google Scholar]

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