title: Crystallography of the integral membrane protein EmrE from Escherichia coli.
abstract: Crystals of the EmrE membrane-protein imposed several technical challenges for X-ray crystallography, including high mosaicity, poor diffraction and a relatively large number of heavy atoms. Consequently, the heavy-atom substructure solution was difficult to obtain. By removing the histidine tag for protein purification, the mosaicity and the diffraction quality were greatly improved. The direct-methods Shake-and-Bake program SnB was successful in locating the heavy-atom sites from a mutant of EmrE which lacks a cysteine and therefore has a reduction in the number of heavy-atom sites. The substructure solution was solved from data with anomalous difference at a resolution of 5.5 A and the structure was determined to 3.8 A.
authors.affiliation: Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, CB-105, La Jolla, CA 92037, USA.
authors.forename: Che
authors.initials: C
authors.lastname: Ma
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Chang
mesh_terms: D017920:Antiporters / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry; D018432:Drug Resistance, Multiple; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006639:Histidine / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry*; D008958:Models, Molecular; D009154:Mutation; D016133:Polymerase Chain Reaction; D011487:Protein Conformation
chemical_list: D017920:Antiporters; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C075436:EmrE protein, E coli; D006639:Histidine; D003545:Cysteine