O V Degtyareva | PubMed Health

PubMed2003

Antimicrobial peptides containing arginine.

Tetradecapeptides (RLARLAR)2, D-(RLARLAR)2, (RLARLAA)2, and (RLGRLGR)2 were synthesized by a solid phase method using Fmoc-amino acids. The antibacterial activity of the synthesized peptides was studied against Escherichia coli cells. The minimum inhibitory concentration (MIC) was, correspondingly, 3, 1, 3, and 12 micro M, which is comparable with MIC of such natural antimicrobial peptides as temporin, magainin, and dermaseptin. It was found that all of the synthesized peptides have no effect on human erythrocytes and rat thymocytes. The peptides form alpha-helices in 30% trifluoroethanol and in 2.5 mM SDS, which have amphipathic structure.

Amino Acid Sequence↗

PubMed2001

FTIR emission spectra of bacteriorhodopsin in a vibrational excited state.

Vibrational IR-emission spectra of bacteriorhodopsin (bR) were recorded under continuous illumination with visible light at room temperature. They contain selective information about the chromophore, Schiff base, and opsin. The spectral bands were identified by comparing the data with resonance Raman and IR absorption data. The IR-emission spectra were shown to contain a set of bands characteristic for both all-trans (bR568) and 13-cis conformations (K610-like intermediate) simultaneously. Variation of spectral composition and the intensity of visible light illumination influenced the spectral traces and intensity distribution between them. Greater intensity of deformational vibrations suggests distorted retinal structure in the vibrationally excited ground electronic state. The origin of the emitting species of bR is discussed.

Bacteriorhodopsins↗