3D9B

Symmetric structure of E. coli AcrB

Summary for 3D9B

• Entry DOI: 10.2210/pdb3d9b/pdb
• Related: 2I6W
• Descriptor: Acriflavine resistance protein B, NICKEL (II) ION (2 entities in total)
• Functional Keywords: alpha-helices, transmembrane protein, inner membrane, transport, transport protein
• Biological source: Escherichia coli
• Cellular location: Cell inner membrane; Multi-pass membrane protein: P31224
• Total number of polymer chains: 1
• Total formula weight: 113723.87

Authors

Veesler, D.,Blangy, S.,Cambillau, C.,Sciara, G. (deposition date: 2008-05-27, release date: 2008-07-01, Last modification date: 2023-08-30)

Primary citation

Veesler, D.,Blangy, S.,Cambillau, C.,Sciara, G.
There is a baby in the bath water: AcrB contamination is a major problem in membrane-protein crystallization.
Acta Crystallogr.,Sect.F, 64:880-885, 2008

PubMed Abstract: In the course of a crystallographic study of the Methanosarcina mazei CorA transporter, the membrane protein was obtained with at least 95% purity and was submitted to crystallization trials. Small crystals (<100 microm) were grown that diffracted to 3.42 A resolution and belonged to space group R32, with unit-cell parameters a = b = 145.74, c = 514.0 A. After molecular-replacement attempts using available CorA structures as search models failed to yield a solution, it was discovered that the crystals consisted of an Escherichia coli contaminating protein, acriflavine resistance protein B (AcrB), that was present at less than 5% in the protein preparations. AcrB contamination is a major problem when expressing membrane proteins in E. coli since it binds naturally to immobilized metal-ion affinity chromatography (IMAC) resins. Here, the structure is compared with previously deposited AcrB structures and strategies are proposed to avoid this contamination.

PubMed: 18931428
DOI: 10.1107/S1744309108028248

Experimental method

X-RAY DIFFRACTION (3.42 Å)