2024-03-28T08:02:31Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1550542021-12-27T15:33:12Zcom_10261_86com_10261_1col_10261_339
Energy transducing roles of antiporter-like subunits in Escherichia coli NDH-1 with main focus on subunit NuoN (ND2)
Sato, Motoaki
Sinha, Prem Kumar
Torres-Bacete, Jesús
Matsuno-Yagi, Akemi
Yagi, Takao
National Institutes of Health (US)
Bioenergetics
Electron Transport System (ETS)
Membrane Energetics
Membrane Enzymes
NADH Dehydrogenase
Site-directed Mutagenesis
13 p.-7 fig.-3 tab.
The proton-translocating NADH-quinone oxidoreductase (complex I/NDH-1) contains a peripheral and a membrane domain. Three antiporter-like subunits in the membrane domain, NuoL, NuoM, and NuoN (ND5, ND4 and ND2, respectively), are structurally similar. We analyzed the role of NuoN in Escherichia coli NDH-1. The lysine residue at position 395 in NuoN (NLys(395)) is conserved in NuoL (LLys(399)) but is replaced by glutamic acid (MGlu(407)) in NuoM. Our mutation study on NLys(395) suggests that this residue participates in the proton translocation. Furthermore, we found that MGlu(407) is also essential and most likely interacts with conserved LArg(175). Glutamic acids, NGlu(133), MGlu(144), and LGlu(144), are corresponding residues. Unlike mutants of MGlu(144) and LGlu(144), mutation of NGlu(133) scarcely affected the energy-transducing activities. However, a double mutant of NGlu(133) and nearby KGlu(72) showed significant inhibition of these activities. This suggests that NGlu(133) bears a functional role similar to LGlu(144) and MGlu(144) but its mutation can be partially compensated by the nearby carboxyl residue. Conserved prolines located at loops of discontinuous transmembrane helices of NuoL, NuoM, and NuoN were shown to play a similar role in the energy-transducing activity. It seems likely that NuoL, NuoM, and NuoN pump protons by a similar mechanism. Our data also revealed that NLys(158) is one of the key interaction points with helix HL in NuoL. A truncation study indicated that the C-terminal amphipathic segments of NTM14 interacts with the Mβ sheet located on the opposite side of helix HL. Taken together, the mechanism of H(+) translocation in NDH-1 is discussed.
This work was supported, in whole or in part, by National Institutes of Health United States Public Health Service Grant GM33712 (to T. Y.).
Peer reviewed
2017-09-13T08:11:05Z
2017-09-13T08:11:05Z
2013-08-23
artículo
http://purl.org/coar/resource_type/c_6501
J Biol Chem. 288(34):24705-16 (2013)
0021-9258
http://hdl.handle.net/10261/155054
10.1074/jbc.M113.482968
1083-351X
http://dx.doi.org/10.13039/100000002
23864658
en
Publisher's version
http://dx.doi.org/ 10.1074/jbc.M113.482968
Sí
open
American Society for Biochemistry and Molecular Biology