Conformational studies on the bacterial cell wall peptide analog phenylacetyl-D-alanyl-D-alanine: Comparison between conformations of cell wall peptide analog and those of penicillin G

Autor: Harald Labischinski, G. Barnickel, H. Bradaczek, W. Rönspeck, Dieter Naumann
Rok vydání: 1985
Předmět:
Zdroj: Biopolymers. 24:2087-2112
ISSN: 1097-0282
0006-3525
DOI: 10.1002/bip.360241107
Popis: The conformation of phenylacetyl-D-alanyl-D-alanine in the crystalline state was characterized by Fourier-transform ir and Raman spectroscopy and was unambiguously solved by x-ray single-crystal determination. In the crystalline state, the molecule adopts a partially folded conformation quite similar to that of another cell wall peptide, acetyl-D-alanyl-D-alanine [Benedetti et al. (1981) J. Biol. Chem.256, 9229–9234], although the crystal structure is stabilized by a quite different intermolecular hydrogen-bond pattern. No significant deviation from the usual trans-planar peptide group geometry was detected. The conformations accessible in the noncrystalline state were investigated by ir measurements in solution and conformational energy calculations. The theoretical study revealed that the peptide is a highly flexible molecule, since 55 minima were detected, within 3 kcal/mol, including the conformation found in the single crystal. The ir data for phenylacetyl-D-alanyl-D-alanine in different solvents were in accordance with virtually extended conformations, with some indication for weak, intramolecularly hydrogen-bonded C5-rings. These conformational data obtained for the cell wall peptide analog are compared with those known for penicillin G in the crystalline state.
Databáze: OpenAIRE
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