gramicidin-a has been researched along with dehydroalanine* in 3 studies
3 other study(ies) available for gramicidin-a and dehydroalanine
| Article | Year |
|---|---|
Synthesis of low-hemolytic antimicrobial dehydropeptides based on gramicidin s.
The synthesis and biological activity of a novel cyclic beta-sheet-type antimicrobial dehydropeptide based on gramicidin S (GS) is described. The GS analogue, containing two (Z)-(beta-3-pyridyl)-alpha,beta-dehydroalanine (DeltaZ3Pal) residues at the 4 and 4' positions (2), was synthesized by solution-phase methodologies using Boc-Leu-DeltaZ3Pal azlactone. Analogue 2 exhibited high antimicrobial activity against Gram-positive bacteria and had much lower hemolytic activity than wild-type GS and the corresponding (Z)-alpha,beta-dehydrophenylalanine (DeltaZPhe) analogue (1). Topics: Alanine; Anti-Bacterial Agents; Circular Dichroism; Gram-Positive Bacteria; Gramicidin; Hemolysis; Magnetic Resonance Spectroscopy; Microbial Sensitivity Tests; Structure-Activity Relationship | 2006 |
Studies of peptide antibiotics. XLVI. Syntheses of gramicidin S analogs containing D-alpha,beta-diaminopropionic acid or alpha,beta-dehydroalanine.
A gramicidin S (GS) analog ([D-Dpr4,4'] GS) containing D-alpha,beta-diaminopropionic acid (D-Dpr) in place of D-Phe at 4,4' positions was derived from [L-Orn(delta-formyl)2,2', D-Dpr(beta-Z)4,4']GS, which was synthesized by conventional method in solution. An analog [delta Ala4,4']GS was synthesized from [L-Orn(delta-Boc)2,2', D-Dpr4,4']GS through Hofmann degradation of the D-Dpr residues. Antimicrobial activities of these analogs were tested; [D-Dpr(beta-Z)4,4']GS and [delta Ala4,4']GS showed high antimicrobial activities against Gram-positive bacteria. [D-Dpr4,4']-GS showed an appreciable activity against Gram-negative bacteria such as Escherichia coli. Four semigramicidin S (semiGS) analogs such as [delta Ala4]semiGS were synthesized; these had no antimicrobial activity. Analogs containing delta Ala residues were hydrogenated, and the formation of L-Ala or D-Ala residues was determined. The delta Ala residues in [delta Ala4,4'] GS were reduced to DL-Ala, and delta Ala in [delta Ala4]semiGS mostly to L-Ala. The relationships of the antimicrobial activity, CD curves and asymmetric hydrogenation to the structure were discussed. Topics: Alanine; beta-Alanine; Gram-Negative Bacteria; Gram-Positive Bacteria; Gramicidin; Hydrogenation; Structure-Activity Relationship | 1985 |
Studies of peptide antibiotics. XLIII. Syntheses of gramicidin S analogs containing D-serine or dehydroalanine in place of D-phenylalanine and asymmetric hydrogenation of the dehydroalanine residue.
Gramicidin S (GS) analogs, [D-Ser4,4']-GS and its precursor [O-benzyl-D-Ser4,4']-GS, were synthesized by the conventional method in order to evaluate the role of the hydroxymethyl side chains in D-Ser at 4,4' positions on the biological activity. Another analog [L-Orn(delta-Boc)2,2',delta Ala4,D-Ser4']-GS was prepared from [D-Ser4,4']-GS by t-butyloxycarbonylation and successive dehydration using dicyclohexylcarbodiimide-CuCl as dehydrating reagent. The delta Ala residue was asymmetrically hydrogenated to D-Ala in the presence of Pd-black. On the microbial assays, [O-benzyl-D-Ser4,4']-GS showed high antimicrobial activity as natural GS, but [D-Ser4,4']-GS showed low activity; the structure-activity relationships of the analogs were discussed. Topics: Alanine; Bacteria; Gramicidin; Indicators and Reagents; Optical Rotation; Phenylalanine; Serine; Structure-Activity Relationship | 1983 |