Background: The advent of human genome sequencing project has led to a spurt in the number of protein sequences in the databanks. Despite significant progresses in the area of experimental protein structure determination, the sequence-structure gap is continually widening. Data driven homology based computational methods have proved successful in predicting tertiary structures for sequences sharing medium to high sequence similarities. With dwindling similarities of query sequences, advanced homology/ ab initio hybrid approaches are being explored to solve structure prediction problem. Here we describe Bhageerath-H, a homology/ ab initio hybrid software/server for predicting protein tertiary structuresto advance drug design attempts.

 Results: Bhageerath-H web-server was validated on 75 CASP10 targets and showed TM-score of > 0.5 in 91% of the cases and Cα RMSDs of < 5Ǻ from the native in 58% of the targets, which is ahead of the current limits. Comparison with some leading servers demonstrated the uniqueness of the hybrid methodology in effectively sampling conformational space, scoring best decoys and refining low resolution models to high and medium resolution.

Conclusion: Bhageerath-H methodology is web enabled for the scientific community as a freely accessible web server at http://www.scfbio-iitd.res.in/bhageerath/bhageerath_h.jsp. The methodology is fielded in the on-going CASP11 experiment.