pH-Dependent Gating in a FocA Formate Channel

The formate transporter FocA was described to switch its mode of operation from a passive export channel at high external pH to a secondary active formate/H⁺ importer at low pH. The crystal structure of Salmonella typhimurium FocA at pH 4.0 shows that this switch involves a major rearrangement of th...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 2011-04, Vol.332 (6027), p.352-354
Main Authors: Lü, Wei, Du, Juan, Wacker, Tobias, Gerbig-Smentek, Elke, Andrade, Susana L. A., Einsle, Oliver
Format: Article
Language:English
Subjects:
Anions
Bacterial Proteins - chemistry
Bacterial Proteins - isolation & purification
Bacterial Proteins - metabolism
Biological and medical sciences
Blocking
Cellular biology
Channels
Crystal structure
Crystalline structure
Crystallization
Crystallography, X-Ray
Crystals
Dehydrogenases
Electrons
Electrophysiology
Exports
Formates
Formates - metabolism
Fundamental and applied biological sciences. Psychology
Gating and risering
Hydrogen-Ion Concentration
Ion Channel Gating
Ion Channels - chemistry
Ion Channels - isolation & purification
Ion Channels - metabolism
Ion Transport
Membrane proteins
Membranes
Metabolites
Models, Molecular
Molecular biology
Molecular biophysics
Protein Conformation
Protein Multimerization
Protein Structure, Quaternary
Protein Structure, Secondary
Protein subunits
Protein Subunits - chemistry
Protein Subunits - metabolism
Proteins
Protons
Salmonella typhimurium - chemistry
Salmonella typhimurium - metabolism
Static Electricity
Structure in molecular biology
Switches
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Summary:The formate transporter FocA was described to switch its mode of operation from a passive export channel at high external pH to a secondary active formate/H⁺ importer at low pH. The crystal structure of Salmonella typhimurium FocA at pH 4.0 shows that this switch involves a major rearrangement of the amino termini of individual protomers in the pentameric channel. The amino-terminal helices open or block transport in a concerted, cooperative action that indicates how FocA is gated in a pH-dependent way. Electrophysiological studies show that the protein acts as a specific formate channel at pH 7.0 and that it closes upon a shift of pH to 5.1.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.1199098