1vk1

Publication Abstract from PubMed

BACKGROUND: The major bottleneck for determination of 3 D structures of proteins using X-rays is the production of diffraction quality crystals. Often proteins are subjected to chemical modification to improve the chances of crystallization RESULTS: Here, we report the successful crystallization of a nuclease employing a reductive methylation protocol. The key to crystallization was the successful introduction of 44 new cohesive (NZ) CH...O contacts (3.2-3.7 A) by the addition of 2 methyl groups to the side chain amine nitrogen (NZ) of 9 lysine residues of the nuclease. The new contacts dramatically altered the crystallization properties of the protein, resulting in crystals that diffracted to 1.2 A resolution. Analytical ultracentrifugation analysis and thermodynamics results revealed a more compact protein structure with better solvent exclusion of buried Trp residues in the folded state of the methylated protein, assisting crystallization. CONCLUSION: In this study, introduction of novel cohesive (NZ)CH...O contacts by reductive methylation resulted in the crystallization of a protein that had previously resisted crystallization in spite of extensive purification and crystallization space screening. Introduction of (NZ)CH...O contacts could provide a solution to crystallization problems for a broad range of protein targets.

(NZ)CH...O contacts assist crystallization of a ParB-like nuclease.,Shaw N, Cheng C, Tempel W, Chang J, Ng J, Wang XY, Perrett S, Rose J, Rao Z, Wang BC, Liu ZJ BMC Struct Biol. 2007 Jul 7;7:46. PMID:17617922^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.