The conformational behaviour of the peptide antibiotic leucinostatin A has been studied in solvents of different polarity using circular dichroism (CD) and infrared (i.r.) absorption. I.r. studies provided evidence of an intramolecularly hydrogen-bonded structure in CDCl3, while CD studies suggested a helical conformation in leucinostatin A in lipophilic solvents. The tetrapeptide Boc-Aib-Leu-Leu-Aib-OMe, a fragment of leucinostatin A, was also studied both in solution and in solid state using X-ray diffraction. The crystal structure shows taht the peptide backbone folds into a right-handed 310-helical conformation stabilized by the two intramoleculr 4 --> 1 hydrogen bonds. The spectroscopic analysis in solution is consistent with the conformation found in solid state.
Structural studies of leucinostatin A and its Boc-Aib-Leu-Aib- OMe tetrapeptide fragment.
RICCI, Maurizio;ROSSI, Carlo;
1989
Abstract
The conformational behaviour of the peptide antibiotic leucinostatin A has been studied in solvents of different polarity using circular dichroism (CD) and infrared (i.r.) absorption. I.r. studies provided evidence of an intramolecularly hydrogen-bonded structure in CDCl3, while CD studies suggested a helical conformation in leucinostatin A in lipophilic solvents. The tetrapeptide Boc-Aib-Leu-Leu-Aib-OMe, a fragment of leucinostatin A, was also studied both in solution and in solid state using X-ray diffraction. The crystal structure shows taht the peptide backbone folds into a right-handed 310-helical conformation stabilized by the two intramoleculr 4 --> 1 hydrogen bonds. The spectroscopic analysis in solution is consistent with the conformation found in solid state.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
