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Species right across the evolutionary scale from insects to mammals use peptides as part of their host-defense system to counter microbial infection. The primary structures of a large number of these host-defense peptides have been determined. While there is no primary structure homology, the peptides are characterized by a preponderance of cationic and(More)
The store-operated calcium channel (SOC) located in the plasma membrane (PM) mediates capacitative entry of extracellular calcium after depletion of intracellular calcium stores in the endoplasmic or sarcoplasmic reticulum (ER/SR). An intimate interaction between the PM and the ER/SR is essential for the operation of this calcium signalling pathway.(More)
Structure and biological activities of synthetic peptides corresponding to bovine neutrophil beta-defensin BNBD-12, GPLSC(1)GRNGGVC(2)IPIRC(3) PVPMRQIGTC(4) FGRPVKC(5) C(6)RSW with disulfide connectivities C(1)-C(5), C(2)-C(4) and C(3)-C(6) and its variants with one, two and three disulfide bridges have been investigated. Selective protection of cysteine(More)
Almost all hemolytic and antimicrobial peptides form part of the defense mechanism of species widely distributed across the evolutionary scale. Although these peptides are of varying lengths and composition, they form amphiphilic structures in a hydrophobic environment. They also have the ability to form channels in natural and model membranes. Hemolytic(More)
The activities of defensins HBD-1, HBD-2, and HBD-3 and their C-terminal analogs Phd1, Phd2, and Phd3 against Candida albicans were investigated. Phd1 to Phd3 showed lower-level activities than HBD-1 to HBD-3, although metabolic inhibitors did not render Phd1 to Phd3 inactive. Their activities were also less salt sensitive than those of HBD-1 to HBD-3.(More)
Mammalian defensins (alpha as well as beta forms) have a beta-hairpin structural motif spanning approximately 20 residues at the carboxy-terminal end. We have investigated the antibacterial activity and biophysical properties of synthetic peptides corresponding to the carboxy-terminal segment of bovine beta-defensin-2 (BNBD-2):(More)
Structure-function relationships in antimicrobial peptides have been extensively investigated in order to obtain improved analogs. Most of these studies have targeted either alpha-helical peptides or beta-sheet peptides with multiple disulfide bridges. Tigerinins are short, nonhelical antimicrobial peptides with a single disulfide bridge. In this study, we(More)
Four broad-spectrum, 11 and 12 residue, novel antimicrobial peptides have been isolated from the adrenaline-stimulated skin secretions of the Indian frog Rana tigerina. Sequences of these peptides have been determined by automated Edman degradation, by mass spectral analysis and confirmed by chemical synthesis. These peptides, which we have named as(More)
The antimicrobial and hemolytic activities of the 13-residue peptide indolicidin (ILPWKWPWWPWRR-NH2), present in bovine neutrophils, and its analogs have been determined with a view to gaining insight into the structural roles of tryptophan and proline. Peptides where proline was replaced by alanine and tryptophan by phenylalanine showed antibacterial(More)
The venom of insects like bee, hornet and wasp contain peptides that exhibit potent biological activities. Many of these peptides are composed of 13-26 residues and are thus accessible through chemical synthesis as well as amenable to studies directed toward structure-function correlations. In this report, we describe antibacterial and hemolytic activities(More)