Structural basis for a homodimeric ATPase subunit of an ECF transporter
Protein & Cell
;
(12): 793-801, 2013.
Article
in English
| WPRIM
| ID: wpr-757552
ABSTRACT
The transition metal cobalt, an essential cofactor for many enzymes in prokaryotes, is taken up by several specific transport systems. The CbiMNQO protein complex belongs to type-1 energy-coupling factor (ECF) transporters and is a widespread group of microbial cobalt transporters. CbiO is the ATPase subunit (A-component) of the cobalt transporting system in the gram-negative thermophilic bacterium Thermoanaerobacter tengcongensis. Here we report the crystal structure of a nucleotide-free CbiO at a resolution of 2.3 Å. CbiO contains an N-terminal canonical nucleotide-binding domain (NBD) and C-terminal helical domain. Structural and biochemical data show that CbiO forms a homodimer mediated by the NBD and the C-terminal domain. Interactions mainly via conserved hydrophobic amino acids between the two C-terminal domains result in formation of a four-helix bundle. Structural comparison with other ECF transporters suggests that non-conserved residues outside the T-component binding groove in the A component likely act as a specificity determinant for T components. Together, our data provide information on understanding of the structural organization and interaction of the CbiMNQO system.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Protein Binding
/
Protein Conformation
/
Structure-Activity Relationship
/
Biological Transport
/
Chemistry
/
Protein Structure, Secondary
/
Cobalt
/
Adenosine Triphosphatases
/
Crystallography, X-Ray
/
Catalytic Domain
Language:
English
Journal:
Protein & Cell
Year:
2013
Type:
Article
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