Defensinpred: defensin and defensin types prediction server.

Defensins are considered to play an important role in the innate immune system of virtually all life forms, from insects and plants to amphibians and mammals. They are classified into alpha, beta and theta-defensins. Fast and accurate computational prediction of defensin and defensin types will help in annotating unidentified defensin novel peptides. Identified defensins, owing to their small length and potent antimicrobial activity can be used effectively for development of new clinically applicable antibiotics. Thus predicting the defensin candidates will aid in accurate identification of novel peptide drugs. Support vector machines prediction model accuracy was 99% for defensin and defensin types. The results indicate that it is most accurate and efficient prediction method for defensin peptides. User friendly defensin web server is provided at www.defensinpred.cdac.in for the benefit of scientific community.

Ultra-stable nanoparticles of CdSe revealed from mass spectrometry.

Nanoparticles under a few nanometres in size have structures and material functions that differ from the bulk because of their distinct geometrical shapes and strong quantum confinement. These qualities could lead to unique device applications. Our mass spectral analysis of CdSe nanoparticles reveals that (CdSe)(33) and (CdSe)(34) are extremely stable: with a simple solution method, they grow in preference to any other chemical compositions to produce macroscopic quantities. First-principles calculations predict that these are puckered (CdSe)(28)-cages, with four- and six-membered rings based on the highly symmetric octahedral analogues of fullerenes, accommodating either (CdSe)(5) or (CdSe)(6) inside to form a three-dimensional network with essentially heteropolar sp(3)-bonding. This is in accordance with our X-ray and optical analyses. We have found similar mass spectra and atomic structures in CdS, CdTe, ZnS and ZnSe, demonstrating that mass-specified and macroscopically produced nanoparticles, which have been practically limited so far to elemental carbon, can now be extended to a vast variety of compound systems.