ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
In chloroform solution, the D,L-alternating stereo-co-oligopeptide HCO-L-Phe-(D-Phe-L-Phe)3-OMe (I) forms three major species, two of which are dimeric and one tetrameric. One of the two dimeric species gives a specific set of 1H-nmr signals at 25°C; the other, together with the tetrameric species, gives another set of resonance signals. In a carbon tetrachloride or cyclohexane solution at 25°C, I forms virtually only the tetrameric species. From the nmr data, it can be shown that the dimeric and tetrameric species, that are in rapid equilibrium with each other in chloroform solutions, are a right-handed ↑↑β5.6 helical dimer and the head-to-head (formyl-ends-to-formyl-ends) dimerization product of this dimer. It is suggested that the linear gramicidins may also form head-to-head dimers of parallel β helices, as observed for the model oligopeptide I.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360231007
