1t55: Difference between revisions

[[Image:1t55.gif|left|200px]]

'''Antibiotic Activity and Structural Analysis of a Scorpion-derived Antimicrobial peptide IsCT and Its Analogs'''

IsCT is a non-cell-selective antimicrobial peptide isolated from the scorpion Opisthacanthus madagascariensis that has potent cytolytic activity against both mammalian and bacterial cells. To investigate the structure-activity relationships of IsCT and to design novel peptide antibiotics with bacterial cell selectivity, we synthesized several analogs of IsCT and determined their three-dimensional structures in solution by 2D-NMR spectroscopy. IsCT has a linear alpha-helical structure from Gly3 to Phe13, and [K7]-IsCT has a linear alpha-helical structure from Leu2 to Phe13. [K7, P8, K11]-IsCT, which has a bend in its middle region, exhibited the highest antibacterial activity without hemolytic activity, suggesting that its proline-induced bend is an important determinant of this selectivity. Tryptophan fluorescence showed that the high selectivity of [K7, P8, K11]-IsCT toward bacterial cells is closely correlated with its highly selective interaction with negatively charged phospholipids. Its potent activity against antibiotic-resistant bacteria suggests that [K7, P8, K11]-IsCT may serve as a promising lead candidate in the development of new peptide antibiotics.

1T55 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Opisthacanthus_madagascariensis Opisthacanthus madagascariensis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1T55 OCA].  

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 09:32:19 2008''