SSEP is a comprehensive resource for accessing information related to the secondary structural elements present in the 25 and 90% non-redundant protein chains. The database contains 1771 protein chains from 1670 protein structures and 6182 protein chains from 5425 protein structures in 25 and 90% non-redundant protein chains, respectively. The current version provides information about the ahelical segments and b-strand fragments of varying lengths. In addition, it also contains the information about 3 10 -helix, b-and m-turns and hairpin loops. The free graphics program RASMOL has been interfaced with the search engine to visualize the threedimensional structures of the user queried secondary structural fragment. The database is updated regularly and is available through Bioinformatics web server at

By exploiting the fast-growing Internet technology, the interactive computing server Water Analysis Package (WAP, version 2.0) has been updated with more flexible options to better understand the role of the water O atoms present in three-dimensional macromolecular (protein or nucleic acid) structures. The updated robust server facilitates the computation and visualization of water molecules from various hydration shells, interfacial water molecules and those water molecules that stabilize various secondary structural elements. It is also possible to detect the interactions of water molecules with various parts (polar atoms, nonpolar atoms, main-chain and side-chain atoms) of the protein molecule. Furthermore, a molecular graphics visualization program is interfaced to display the nature of the interactions of the water molecules. The Protein Data Bank archive interfaced with the server is updated every week; hence users get to analyse the latest structures. The computing server can be obtained from

The Conformation Angles Data Base (CADB) is a comprehensive, authoritative and timely knowledge base with a powerful query engine developed to facilitate the retrieval of information related to the conformational angles (main chain and side chain) of the amino-acid residues present in non-redundant (both 25 and 90%) data sets. The updated version has improved options for determining the dependency of the conformation angles of a particular residue upon the flanking residues, doublet analysis, triplet analysis and analysis of a particular protein structure. It is worth mentioning that for all options a user-friendly and convenient Java graphical user interface (GUI) has been provided to display the output on the client machine. The database is accessible at the URL http://cluster.physics.iisc.ernet.in/cadb/ or http://144.16.71.148/cadb/.

The interaction of zwitterionic lipid DMPC and DPPC with cyclic hexapeptide, cyclo (D-Ala-L-Pro-L-Ala)2 was studied using circular dichroism (CD) and differential scanning calorimetry (DSC). Preliminary membrane conductance results showed that the peptide has a tendency to form channels inside the lipid bilayer. CD studies indicated that as the lipid/peptide (L/P) ratio (DMPC/peptide) was increased, the magnitude of the negative CD band having a lambda(max) around 200 nm decreased. At a L/P ratio of 210:1, this band disappeared completely, indicating dramatic conformational changes in the peptide on interaction with the lipid bilayer. Reduction of the phase transition temperature and the maximum heat capacity of the lipid bilayer (DPPC) for gel-to-liquid crystalline phase transition indicates a strong interaction of the peptide with the lipid bilayer.

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