ISSN:
1572-9001
Keywords:
Cyclicβ-casomorphins
;
conformational analysis
;
NMR spectroscopy
;
cyclic pentapeptides
;
force field calculations
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The solution conformation of two cyclicβ-casomorphin-5 analogues H-Tyr-c(-d-Orn-Phe-Pro-Gly-)1 and H-Tyr-c(-Orn-Phe-Pro-Gly-)2 in DMSO-d 6 was studied by NMR spectroscopy and accompanying force field calculations. By especially employing1H,13C, and15N chemical shifts, respectively, the temperature coefficient of the amide proton chemical shifts,3 J NH,CαH andJ CαH.CβH coupling constants, respectively, and nuclear Overhauser effects in the rotating frame (ROEs), in the case of1, only one preferred conformer could be identified. In the case of2, two or even more preferred conformers were found, readily interconverting on the NMR time scale. Empirical force field calculations using the SYBYL 6.0 software (TRIPOS) corroborate the experimental NMR results obtained. The conformational behavior of the compounds studied is discussed with respect to the receptor specificity of theβ-casomorphins studied.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02278739
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