Normal mode refinement of anisotropic thermal parameters for a supramolecular complex at 3.42-A crystallographic resolution.

ABSTRACT: Here we report a normal-mode-based protocol for modeling anisotropic thermal motions of proteins in x-ray crystallographic refinement. The foundation for this protocol is a recently developed elastic normal mode analysis that produces much more accurate eigenvectors without the tip effect. The effectiveness of the procedure is demonstrated on the refinement of a 3.42-A structure of formiminotransferase cyclodeaminase, a 0.5-MDa homooctameric enzyme. Using an order of magnitude fewer adjustable thermal parameters than the conventional isotropic refinement, this protocol resulted in a decrease of the values of R(cryst) and R(free) and improvements of the density map. Several poorly resolved regions in the original isotropically refined structure became clearer so that missing side chains wer

SUBMITTER: Poon BK 

PROVIDER: S-EPMC1876539 | biostudies-literature | 2007 May

REPOSITORIES: biostudies-literature