PMID:25448817

Citation	Mayer, S, Steffen, W, Steuber, J and Götz, F (2015) The Staphylococcus aureus NuoL-like protein MpsA contributes to the generation of membrane potential. J. Bacteriol. 197:794-806
Abstract	In aerobic microorganisms, the entry point of respiratory electron transfer is represented by the NADH:quinone oxidoreductase. The enzyme couples the oxidation of NADH with the reduction of quinone. In the type 1 NADH:quinone oxidoreductase (Ndh1), this reaction is accompanied by the translocation of cations, such as H(+) or Na(+). In Escherichia coli, cation translocation is accomplished by the subunit NuoL, thus generating membrane potential (Δψ). Some microorganisms achieve NADH oxidation by the alternative, nonelectrogenic type 2 NADH:quinone oxidoreductase (Ndh2), which is not cation translocating. Since these enzymes had not been described in Staphylococcus aureus, the goal of this study was to identify proteins operating in the NADH:quinone segment of its respiratory chain. We demonstrated that Ndh2 represents a NADH:quinone oxidoreductase in S. aureus. Additionally, we identified a hypothetical protein in S. aureus showing sequence similarity to the proton-translocating subunit NuoL of complex I in E. coli: the NuoL-like protein MpsA. Mutants with deletion of the nuoL-like gene mpsA and its corresponding operon, mpsABC (mps for membrane potential-generating system), exhibited a small-colony-variant-like phenotype and were severely affected in Δψ and oxygen consumption rates. The MpsABC proteins did not confer NADH oxidation activity. Using an Na(+)/H(+) antiporter-deficient E. coli strain, we could show that MpsABC constitute a cation-translocating system capable of Na(+) transport. Our study demonstrates that MpsABC represent an important functional system of the respiratory chain of S. aureus that acts as an electrogenic unit responsible for the generation of Δψ.
Links	PubMed PMC4325100 Online version:10.1128/JB.02127-14
Keywords	Amino Acid Sequence; Base Sequence; Biological Transport; Escherichia coli/genetics; Escherichia coli/physiology; Escherichia coli Proteins/genetics; Escherichia coli Proteins/metabolism; Membrane Potentials; Molecular Sequence Data; NADH Dehydrogenase/chemistry; NADH Dehydrogenase/genetics; NADH Dehydrogenase/metabolism; Operon; Oxidation-Reduction; Oxygen/metabolism; Sequence Alignment; Sodium/metabolism; Staphylococcus aureus/chemistry; Staphylococcus aureus/enzymology; Staphylococcus aureus/genetics; Staphylococcus aureus/physiology
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
STAA8:Q2G0W2		GO:0045838: positive regulation of membrane potential	ECO:0000315:		P		Figure 5A	complete CACAO 10970
STAA8:Q2G0W2		GO:0005887: integral component of plasma membrane	ECO:0000250:	UniProtKB:P33607	C		Figure 2; there was an alignment done to E. coli NuoL (accession no. P33607) and a TMHMM.	complete CACAO 10971
STAA8:Q2G0W2		GO:0016491: oxidoreductase activity	ECO:0000315:		F		Figure 7	complete CACAO 10972
STAA8:Q2G0W2		GO:0019646: aerobic electron transport chain	ECO:0000315:		P		Figure 7 - Oxygen consumption rates decreased in MpsA and MpsABC mutants, but increased in MpsA containing cells.	complete CACAO 10973
STAA3:Y844		GO:0050136: NADH dehydrogenase (quinone) activity	ECO:0000315:		F		Figure 6B	complete CACAO 10969

References

See Help:References for how to manage references in GONUTS.