Mechanisms of drug/H+ antiport: complete cysteine-scanning mutagenesis and the protein engineering approach.
The notorious difficulty of elucidating structures of membrane transporters by crystallography has long prevented our understanding of active transport mechanism coupled with ion/proton transport. The determination of the first crystal structure of the drug/H+ antiporter AcrB was a breakthrough for structure-based understanding of drug/H+ antiport. However, although AcrB is a major multidrug exporter in Gram-negative organisms, the majority of bacterial drug exporters are major facilitator superfamily (MFS) drug transporters. As no crystal structures have been solved for MFS transporters, the alternative protein-engineering methods are still very useful for estimating structures and functions of drug/H+ antiporters. This review describes this alternative approach for investigating the structure and function of tetracycline/H+ antiporters.
Department of Cell Membrane Biology, Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
Norihisa
N
Tamura
Satoko
S
Konishi
Akihito
A
Yamaguchi
D000595:Amino Acid Sequence; D017920:Antiporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D003545:Cysteine / Q000737:chemistry*; D004563:Electrochemistry; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016297:Mutagenesis, Site-Directed; D015202:Protein Engineering; D017433:Protein Structure, Secondary; D013754:Tetracyclines / Q000378:metabolism* / Q000494:pharmacology
D017920:Antiporters; D001426:Bacterial Proteins; D013754:Tetracyclines; C079051:tetA protein, Bacteria; D003545:Cysteine