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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)
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)
The antibacterial activity of peptides without disulfide bridges, spanning the carboxy-terminal segment of arthropod defensins, has been investigated. Although all the peptides have net positive charges, they exhibited varying antibacterial potencies and spectra. Atomic force and fluorescence microscopic analyses indicate that the peptides exert their(More)
Mammalian defensins are crucial components of the innate immune system. They are characterized by three disulfide bridges and exhibit broad spectrum antibacterial activity. The spacing between the cysteines and disulfide connectivities in the two classes of defensins, the alpha- and beta-forms, are different. The structural motif of 3 beta-strands appears(More)
The ryanodine receptor/Ca(2+) release channels from skeletal (RyR1) and cardiac (RyR2) muscle cells exhibit different inactivation profiles by cytosolic Ca(2+). D3 is one of the divergent regions between RyR1 (amino acids (aa) 1872-1923) and RyR2 (aa 1852-1890) and may contain putative binding site(s) for Ca(2+)-dependent inactivation of RyR. To test this(More)
We demonstrate that antimicrobial peptides induce an autophagic cell death in the protozoan pathogen, Leishmania donovani. In our study, three antimicrobial peptides, Indolicidin, and two peptides derived from Seminalplasmin exhibit antileishmanial activity with a 50% lethal dose of 3.5 x 10(-5), 3.8 x 10(-4) and 1.7 x 10(-8) microM, respectively. The(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)