IDEAFIX is a decision tree-based variant refinement tool that filters formaldehyde-induced cytosine deaminations from variant lists obtained from DNA sequencing data from FFPE specimens.
QRNAS (Quick Refinement of Nucleic Acid Structures) is an extension of the AMBER simulation method with additional terms associated with explicit hydrogen bonds, co-planarity base pairs, backbone regularization, and custom restraints. QRNAS is capable of handling RNA, DNA, chimeras and hybrids thereof, and enables modeling of nucleic acids containing modified residues.
Flex-EM includes a rigid fitting stage followed by a refinement stage. Rigid fitting can be performed with Mod-EM or any other rigid fitting methods. The refinement stage starts with the components rigidly fitted in the approximate positions in the map. Two methods are available: conjugate gradients minimization (CG) and simulated annealing molecular dynamics (MD).
PULCHRA (PowerfUL CHain Restoration Algorithm) is a simple command-line tool for all-atom reconstruction and refinement of reduced protein models. PUCLHRA can correct alpha carbon positions, add backbone and side chain atoms, improve hydrogen bonds patterns and check proper protein chirality.
FG-MD is a molecular dynamics (MD) based algorithm for atomic-level protein structure refinement. Given an initial protein structure, FG-MD first identifies analogous fragments from the PDB by the structural alignment program TM-align. Spatial restraints extracted from the fragments are then used to to re-shape the funnel of the MD energy landscape and guide the MD conformational sampling. FG-MD aims to refine the initial models closer to the native structure. It can also improve the local geometry of the structures by removing the steric clashes and improving the torsion angle and the hydrogen-binding networks.
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.
Dong Xu and Yang Zhang.
Improving Physical Realism and Structural Accuracy of Protein Models by a Two-step Atomic-level Energy Minimization
(in preparation).
MONGOOSE (MetabOlic Network GrOwth Optimization Solved Exactly) is a package for structural analysis and refinement of constraint-based metabolic networks. Unlike other existing software, MONGOOSE uses exact rational arithmetic, which makes its results certifiably accurate.
i3Drefine is a completely automated and computationally efficient protein 3D structure refinement method which based on an iterative and highly convergent energy minimization algorithm with a powerful all-atom composite physics and knowledge-based force fields and hydrogen bonding (HB) network optimization technique.