PMID: 22297987

Authors:

Liu W, Macgrath SM, Koleske AJ, Boggon TJ

Title:

Lysozyme contamination facilitates crystallization of a heterotrimeric cortactin-Arg-lysozyme complex.

Journal:

Acta Crystallogr Sect F Struct Biol Cryst Commun. 2012 Feb 1;68(Pt, 2):154-8. Epub 2012 Jan 25.

Abstract:

Crystallization of contaminating proteins is a frequently encountered problem for macromolecular crystallographers. In this study, an attempt was made to obtain a binary cocrystal structure of the SH3 domain of cortactin and a 17-residue peptide from the Arg nonreceptor tyrosine kinase encompassing a PxxPxxPxxP (PxxP1) motif. However, cocrystals could only be obtained in the presence of trace amounts of a contaminating protein. A structure solution obtained by molecular replacement followed by ARP/wARP automatic model building allowed a `sequence-by-crystallography' approach to discover that the contaminating protein was lysozyme. This 1.65 A resolution crystal structure determination of a 1:1:1 heterotrimeric complex of Arg, cortactin and lysozyme thus provides an unusual `caveat emptor' warning of the dangers that underpurified proteins harbor for macromolecular crystallographers.