Protein structure prediction and conformational transitions

Abstract

There is a critical need for protein structure and function prediction. Accurate protein secondary structure prediction is essential for many bioinformatics applications, including protein tertiary structure prediction. We developed an algorithm (Fragment Data Mining, FDM) for protein secondary structure prediction using fragments of known structures obtained by multiple sequence alignment (MSA). Its performance is excellent where highscore MSA matches are available. By combing it with GOR V, a new Consensus Database Mining (CDM) method was developed, which surpasses the performances of both FDM and GOR V. For each residue, it chooses to use either the result of FDM or GOR V depending upon the availability of high-score matches of MSA. A server has been set up to make CDM publicly accessible. It becomes more popular due to the reliability and efficiency of its performance, the simplicity of its use, and its potential for improvement with the rapidly growing number of determined structrues. Phosphorylation is the most important post translational modifications for cellular regulation and signal transduction. Upon phosphorylation, proteins can undergo obvious conformational changes. It is challenging to characterize these changes because of the high flexibility of phosphorylation regions and the difficulties in obtaining diffraction quality crystals. In the current study, we focused on the conformational changes of CDK2 due to phosphorylation at Thr160. We use C-C-side chain (CABS) modeling, Targeted Molecular Dynamics (TMD) and conventional molecular dynamics (MD) to simulate the structural transition and create transition pathways. Principal component analysis (PCA) of the trajectories and normal mode analysis (NMA) with anisotropic network model (ANM – an