Automated genome sequencing procedure is enriching the sequence database very fast. To achieve a balance between the entry of sequences in the database and their analyses, efficient software is required. In this end PHYSICO2, compare to earlier PHYSICO and other public domain tools, is most efficient in that it i] extracts physicochemical, window-dependent and homologousposition-based-substitution (PWS) properties including positional and BLOCK-specific diversity and conservation, ii] provides users with optional-flexibility in setting relevant input-parameters, iii] helps users to prepare BLOCK-FASTA-file by the use of Automated Block Preparation Tool of the program, iv] performs fast, accurate and user-friendly analyses and v] redirects itemized outputs in excel format along with detailed methodology. The program package contains documentation describing application of methods. Overall the program acts as efficient PWS-analyzer and finds application in sequence-bioinformatics.

Component (bridge: Delta Delta G(brd), background: Delta Delta G(prot), desolvation: Delta Delta G(dsolv)) and net (Delta Delta G(net)) energy-terms of salt-bridge-structure (SBS) are auto-generated by the program ADSBET that makes use of general purpose Adaptive Poison Boltzmann Solver (APBS) method. While the procedure reports gross energy terms (Kcal Mol(-1)), report on bond-multiplicity corrected normalized energyterms (Kcal Mol(-1) Bond(-1)) along with their accessibility (ASA) in monomer, isolated-SBS (ISBS) and networked-SBS (NSBS) format would be very useful for statistical comparison among SBSs and understanding their location in protein structure. In this end, ADSBET2 potentially incorporates these features along with additional model for side-chain. Gross and normalized energy-terms are redirected in monomer, ISBS and NSBS format along with their ASA informations. It works on any number of SBSs for any number of structure files present in a database. Taken together, ADSBET2 has been suitable for statistical analyses of SBSs energetics and finds applications in protein engineering and structural bioinformatics.

Specific electrostatics (i.e. salt-bridge) includes both local and non-local interactions that contribute to the overall stability of proteins. It has been shown that a salt-bridge could either be buried or exposed, networked or isolated, hydrogen-bonded or non-hydrogen bonded, in secondary-structure or in coil, formed by single or multiple bonds. Further it could also participates either in intra- or inter-dipole interactions with preference in orientation either for basic residue at N-terminal (orientation-I) or acidic residue at N-terminal (orientation-II). In this context SBION2 is unique in that it reports above mentioned binary items in excel format along with details on intra and inter-dipole interactions and orientations. These results are suitable for post run statistical analyses involving large datasets. Reports are also made on protein-protein interactions, intervening residue distances and general residue specific salt-bridge details. A ready to use compact supplementary table is also produced. The program runs in three alternative modes. Each mode works on any number of structure files with any number of chains at any given atomic distance of ion-pair. Thus SBION2 provides intricate details on salt-bridges and finds application in structural bioinformatics.