Properties of synthetic analogs of gramicidin S containing L-serine or L-glutamic acid residue in place of L-ornithine residue.
In order to investigate the biological role of the delta-amino groups of the Orn residue in gramicidin S, the four analogs, [Ser2]-, [Ser2.2']-, [Glu2]- and [Glu2.2']-gramicidin S were synthesized by a solution method. Except for the last one, these analogs show antibiotic activity to a certain extent against gram-positive micro-organisms, but the activites are weaker than that of gramicidin S. These results indicate that the delta-amino group of the Orn residue is quite important for exhibiting of the activity of gramicidin S, but is not essential to the activity. NMR and CD studies of these analogs indicate that these analogs possess four intramolecular hydrogen bonds between the Val and Leu residues similar to those of GS, and the removal or diminution of the delta-amino group of ornithine residues give the considerable influence to the dihedral angle of NxH-CxH of D-Phe residues and consequently affect the type II' beta-turn structure of the cyclic peptides.
Tamaki
M
M
Department of Chemistry, Faculty of Science, Toho University, China, Japan.
Akabori
S
S
Muramatsu
I
I
D018698:Glutamic Acid / Q000737:chemistry; D006096:Gramicidin / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry; D009952:Ornithine / Q000737:chemistry; D012694:Serine / Q000737:chemistry
D006096:Gramicidin; D018698:Glutamic Acid; D012694:Serine; D009952:Ornithine