Crystallization and preliminary X-ray diffraction analysis of three EGF domains of EMR2, a 7TM immune-system molecule

Abstract

Crystals of three epidermal growth-factor-like (EGF) domains of EMR2 (143 residues) have been grown. EMR2 is a member of the EGF-TM7 family of proteins. Different splice variants exist with between three and five consecutive EGF modules linked to a seven-span transmembrane G-protein-coupled receptor. Although its precise function is unknown, EMR2 is highly expressed in immune tissues and has been shown to weakly bind CD55, a complement-system regulator. Here, crystallization of EMR2 in the presence of Ca2+, Ba 2+ and Sr2+ ions is reported. A complete data set has been collected from all three crystal types, all of which belong to space group P21. An anomalous Patterson map from the Ba2+ crystal data reveals three Ba2+ ions bound within the asymmetric unit. © 2004 International Union of Crystallography. Printed in Denmark - all rights reserved.