Summary for 3OW7
| Entry DOI | 10.2210/pdb3ow7/pdb |
| Related | 3OOC 3OPO |
| Descriptor | Cation efflux system protein cusB, COPPER (I) ION (2 entities in total) |
| Functional Keywords | three-helix bundle, beta barrel, copper transport, ion transport, transport, transport protein |
| Biological source | Escherichia coli |
| Total number of polymer chains | 2 |
| Total formula weight | 90613.36 |
| Authors | Su, C.-C. (deposition date: 2010-09-17, release date: 2010-11-17, Last modification date: 2024-02-21) |
| Primary citation | Su, C.C.,Yang, F.,Long, F.,Reyon, D.,Routh, M.D.,Kuo, D.W.,Mokhtari, A.K.,Van Ornam, J.D.,Rabe, K.L.,Hoy, J.A.,Lee, Y.J.,Rajashankar, K.R.,Yu, E.W. Crystal structure of the membrane fusion protein CusB from Escherichia coli. J.Mol.Biol., 393:342-355, 2009 Cited by PubMed Abstract: Gram-negative bacteria, such as Escherichia coli, frequently utilize tripartite efflux complexes belonging to the resistance-nodulation-division family to expel diverse toxic compounds from the cell. These systems contain a periplasmic membrane fusion protein (MFP) that is critical for substrate transport. We here present the x-ray structures of the CusB MFP from the copper/silver efflux system of E. coli. This is the first structure of any MFPs associated with heavy-metal efflux transporters. CusB bridges the inner-membrane efflux pump CusA and outer-membrane channel CusC to mediate resistance to Cu(+) and Ag(+) ions. Two distinct structures of the elongated molecules of CusB were found in the asymmetric unit of a single crystal, which suggests the flexible nature of this protein. Each protomer of CusB can be divided into four different domains, whereby the first three domains are mostly beta-strands and the last domain adopts an entirely helical architecture. Unlike other known structures of MFPs, the alpha-helical domain of CusB is folded into a three-helix bundle. This three-helix bundle presumably interacts with the periplasmic domain of CusC. The N- and C-termini of CusB form the first beta-strand domain, which is found to interact with the periplasmic domain of the CusA efflux pump. Atomic details of how this efflux protein binds Cu(+) and Ag(+) were revealed by the crystals of the CusB-Cu(I) and CusB-Ag(I) complexes. The structures indicate that CusB consists of multiple binding sites for these metal ions. These findings reveal novel structural features of an MFP in the resistance-nodulation-division efflux system and provide direct evidence that this protein specifically interacts with transported substrates. PubMed: 19695261DOI: 10.1016/j.jmb.2009.08.029 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.78 Å) |
Structure validation
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