Quinone‐interacting membrane‐bound oxidoreductase comple. Probable electron donor/transfer to Apr, linked to menaquinone pool. Appears specific for sulfate reduction pathway, but not sulfite reduction; reverse function in sulfur oxidation.

MATNGSKEGNGGNGNGGLILVIGGGIAGMTAALEAAEAGCEVVLVEKSAYLGGRVARFHQ YFPKLCPPACGVEINLKRLKNNRQVTILTQAEVESLRGTPGDYEAVINLAPRYVTDACTL CGECLKVCPADVADEFNYSLSKTKAIHLPHAMAFPAKYVVERSACPESCHACVDVCAYRA IDLMQKAEKKTLRVASVIVATGWAPYDAAKIENLGFGRCANVVTNVMVERFAAANGPTAG KILRPSDGKEPRSVAFVQCAGSRDQNHLPYCSAVCCSASLKHATYVRKLYPEAEITIFYI DLRTPGNLQNFYAKVTAENKIELIKGKVGKVEEDPATREVVVTVEDVLHGTKIKRNYDLV VLATGMVPQTGGLPAVVDLDEFGFVNNMNTNVNTGVYGTGCVKRPAEVSGTIRDATGVAL KALQITVGATHLGVEQHG445

	PMID	Title & Author	Abstract	Year
0	22536198	The Membrane QmoABC Complex Interacts Directly with the Dissimilatory Adenosine 5'-Phosphosulfate Reductase in Sulfate Reducing Bacteria. Ramos AR, Keller KL, Wall JD, Pereira IA.	The adenosine 5'-phosphosulfate reductase (AprAB) is the enzyme responsible for the reduction of adenosine 5'-phosphosulfate (APS) to sulfite in the biological process of dissimilatory sulfate reduction, which is carried out by a ubiquitous group of sulfate reducing prokaryotes. The electron donor for AprAB has not been clearly identified, but was proposed to be the QmoABC membrane complex, since an aprBA-qmoABC gene cluster is found in many sulfate reducing and sulfur-oxidizing bacteria. The QmoABC complex is essential for sulfate reduction, but electron transfer between QmoABC and AprAB has not been reported. In this work we provide the first direct evidence that QmoABC and AprAB interact in Desulfovibrio spp., using co-immunoprecipitation, cross-linking Far-Western blot, tag-affinity purification, and surface plasmon resonance studies. This showed that the QmoABC-AprAB complex has a strong steady-state affinity (K(D) = 90 ± 3 nM), but has a transient character due to a fast dissociation rate. Far-Western blot identified QmoA as the Qmo subunit most involved in the interaction. Nevertheless, electron transfer from menaquinol analogs to APS through anaerobically purified QmoABC and AprAB could not be detected. We propose that this reaction requires the involvement of a third partner to allow electron flow driven by a reverse electron bifurcation process, i.e., electron confurcation. This process is deemed essential to allow coupling of APS reduction to chemiosmotic energy conservation.	2012
1	23842468	Membrane protein complex of APS reductase and Qmo is present in Desulfovibrio vulgaris and Desulfovibrio alaskensis. Krumholz LR, Wang L, Beck DAC, Wang T, Hackett M, Mooney B, Juba TR, McInerney MJ, Meyer B, Wall JD, Stahl DA.	Due to their adjacent location in the genomes of Desulfovibrio species and their potential for formation of an electron transfer pathway in sulfate-reducing prokaryotes, adenosyl phosphosulfate (APS) reductase (Apr) and quinone-interacting membrane-bound oxidoreductase (Qmo) have been thought to interact together during the reduction of APS. This interaction was recently verified in Desulfovibrio desulfuricans. Membrane proteins of Desulfovibrio vulgaris Hildenborough ΔqmoABCD JW9021, a deletion mutant, were compared to the parent strain using blue-native PAGE to determine whether Qmo formed a complex with Apr or other proteins. In the parent strain of D. vulgaris, a unique band was observed that contained all four Qmo subunits, and another band contained three subunits of Qmo, as well as subunits of AprA and AprB. Similar results were observed with bands excised from membrane preparations of Desulfovibrio alaskensis strain G20. These results are in support of the formation of a physical complex between the two proteins; a result that was further confirmed by the co-purification of QmoA/B and AprA/B from affinity-tagged D. vulgaris Hildenborough strains (AprA, QmoA and QmoB) regardless of which subunit had been tagged. This provides clear evidence for the presence of a Qmo-Apr complex that is at least partially stable in protein extracts of D. vulgaris and D. alaskensis.	2013

Ramos, A.R., Keller, K.L., Wall, J.D., and Pereira, I.A.C. (2012) The membrane QmoABC complex interacts directly with the dissimilatory adenosine 5 ′‐phosphosulfate reductase sulfate reducing bacteria. Front Microbiol 3: 137.