Structural basis for a homodimeric ATPase subunit of an ECF transporter.
10.1007/s13238-013-3915-y
- Author:
Chengliang CHAI
1
;
You YU
;
Wei ZHUO
;
Haifeng ZHAO
;
Xiaolu LI
;
Na WANG
;
Jijie CHAI
;
Maojun YANG
Author Information
1. College of Biological Sciences, China Agricultural University, Beijing, 100083, China.
- Publication Type:Journal Article
- MeSH:
Adenosine Triphosphatases;
chemistry;
Amino Acids;
chemistry;
Biological Transport;
Catalytic Domain;
Cobalt;
chemistry;
Crystallography, X-Ray;
Protein Binding;
Protein Conformation;
Protein Structure, Secondary;
Structure-Activity Relationship;
Thermoanaerobacter;
enzymology
- From:
Protein & Cell
2013;4(10):793-801
- CountryChina
- Language:English
-
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.
