ModRefiner is an algorithm for atomic-level, high-resolution protein structure refinement, which can start from either C-alpha trace, main-chain model or full-atomic model. Both side-chain and backbone atoms are completely flexible during structure refinement simulations, where conformational search is guided by a composite of physics- and knowledge-based force field. ModRefiner has an option to allow for the assignment of a second structure which will be used as a reference to which the refinement simulations are driven. One aim of ModRefiner is to draw the initial starting models closer to their native state, in terms of hydrogen bonds, backbone topology and side-chain positioning. It also generates significant improvement in physical quality of local structures. The standalone program also supports ab initio full-atomic relaxation, where the refined model is not restrainted by the initial model or the reference model.

Go to Job M11 to view an example of ModRefiner output. The current version only supports single-chain model.

Cut and paste the structure you want to refine (C-alpha trace, main-chain model or full-atomic model) in PDB format here: Or upload the target structure file from your local computer: Upload a reference structure (only C-alpha trace required) to which the refined model will be driven (Optional): Email (Mandatory, where results will be sent to):

• WindowsXP version
• Linux version
• Mac version

• 2011/05/05: The first version is released.
• 2011/10/24: The residue number doesn't need to start from 1. The program terminates after a fixed number of cycles rather than running time.