Dynamics of βB2-Crystallin Motion Based on Principal Component Analysis and Normal Mode Analysis

The primary function of lens is to focus images perfectly on the retina. Lens crystallins however are flexible nanomachines that frequently accomplish their biological function by collective atomic motions in and/or out the lens. Although genetic and biochemical data on the βB2-crystallin protein are available from several sources, the correlation between conformational changes and dynamic behavior at the atomic level remains to be understood. The βB2-crystallin dimer has studied through a combination of molecular dynamics simulations, principal component analysis (PCA) and normal mode analyses. The changes in interface buried surface shows the mutual orientation of individual domains in βB2-crystallin dimer. The dominant PCA modes for concerted motions of the protein atoms were monitored in a lower-dimensions subspace. Three types of movements found in βB2-crystallin dimer, which are a twist propeller motion, a scissors type hinge motion, and a shear motion between the domains. Both the RMSF and the normal-mode dynamics showed that N-terminal β-sheet is the most correlated segments.