Oligomeric behavior of the RND transporters CusA and AcrB in micellar solution of detergent

• Published in: Biochimica et biophysica acta Vol. 1768; no. 6; pp. 1567 - 1573
• Main Authors: Stroebel, David, Sendra, Véronique, Cannella, Dominique, Helbig, Kerstin, Nies, Dietrich H., Covès, Jacques
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2007
• Subjects: Analytical ultracentrifugation; Crystallization; Detergent; Detergents - chemistry; Escherichia coli Proteins - chemistry; Hydrogen-Ion Concentration; Membrane protein; Membrane Transport Proteins - chemistry; Micelles; Multidrug Resistance-Associated Proteins - chemistry; Oligomer; Protein Binding; Protein Conformation; RND transporter; Ultracentrifugation; FC14; RND transporter; Membrane protein; Detergent; FTIR; Crystallization; RND; DDM; Analytical ultracentrifugation; Oligomer; AUC
• ISSN: 0005-2736; 0006-3002; 1879-2642
• DOI: 10.1016/j.bbamem.2007.03.008

We have used analytical ultracentrifugation to explore the oligomeric states of AcrB and CusA in micellar solution of detergent. These two proteins belong to the resistance, nodulation and cell division (RND) family of efflux proteins that are involved in multiple drug and heavy metal resistance. Only the structure of AcrB has been determined so far. Although functional RND proteins should assemble as trimers as AcrB does, both AcrB and CusA form a mixture of quaternary structures (from monomer to heavy oligomer) in detergent solution. The distribution of the oligomeric states was studied as a function of different parameters: nature and concentration of the detergent, ionic strength, pH, protein concentration. This pseudo-heterogeneity does not hamper the crystallization of AcrB as a homotrimer.