title: High-resolution diffraction from crystals of a membrane-protein complex: bacterial outer membrane protein OmpC complexed with the antibacterial eukaryotic protein lactoferrin.
abstract: Crystals of the complex formed between the outer membrane protein OmpC from Escherichia coli and the eukaryotic antibacterial protein lactoferrin from Camelus dromedarius (camel) have been obtained using a detergent environment. Initial data processing suggests that the crystals belong to the hexagonal space group P6, with unit-cell parameters a = b = 116.3, c = 152.4 A, alpha = beta = 90, gamma = 120 degrees. This indicated a Matthews coefficient (VM) of 3.3 A3 Da(-1), corresponding to a possible molecular complex involving four molecules of lactoferrin and two porin trimers in the unit cell (4832 amino acids; 533.8 kDa) with 63% solvent content. A complete set of diffraction data was collected to 3 A resolution at 100 K. Structure determination by molecular replacement is in progress. Structural study of this first surface-exposed membrane-protein complex with an antibacterial protein will provide insights into the mechanism of action of OmpC as well as lactoferrin.
authors.affiliation: Department of Genetic Engineering, School of Biotechnology, Madurai Kamaraj University, Madurai 625021, India.
authors.forename: N
authors.initials: N
authors.lastname: Sundara Baalaji
authors.forename: K Ravi
authors.initials: KR
authors.lastname: Acharya
authors.forename: T P
authors.initials: TP
authors.lastname: Singh
authors.forename: S
authors.initials: S
authors.lastname: Krishnaswamy
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry*; D002162:Camelus; D003460:Crystallization; D004058:Diffusion; D004926:Escherichia coli / Q000737:chemistry*; D007781:Lactoferrin / Q000737:chemistry*; D018272:Porins / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; C113724:OmpC protein; D018272:Porins; D007781:Lactoferrin