HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (Papers in Press[PDF]) All Versions of this Article: mic.0.025205-0v1 155/7/2137    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Kajiyama, Y. Articles by Kosono, S. Search for Related Content PubMed PubMed Citation Articles by Kajiyama, Y. Articles by Kosono, S. Agricola Articles by Kajiyama, Y. Articles by Kosono, S.

The MrpA, MrpB, and MrpD subunits of the Mrp antiporter complex in Bacillus subtilis contain membrane-embedded and essential acidic residues

¹ Riken, Shinshu Univ.;
² Riken;
³ Shinshu Univ;
⁴ Riken, Yokohama City Univ

ABSTRACT

Bacillus subtilis Mrp is a particularly unique Na+/H+ antiporter with a multicomponent structure consisting of the mrpABCDEFG gene products. We have previously reported that the conserved and putative membrane-embedded Glu-113, Glu-657, Asp-743, and Glu-747 of MrpA (ShaA) are essential for the transport function. In this study, we further investigated the functional involvement of such conserved acidic residues of other Mrp proteins in heterologous Escherichia coli and natural B. subtilis backgrounds. Asp-121 of MrpB and Glu-137 of MrpD were additionally identified to be essential for the transport function in both systems. Glu-137 of MrpD and Glu-113 of MrpA were found to be conserved in the homologous MrpD/MrpA proteins as well as in their homologous subunits of H+-translocating primary active transporters such as Nuo and Mbh, suggesting their critical role in ion binding. The remaining essential acidic residues clustered in the C-terminal domain of MrpA (Glu-657, Asp-743, and Glu-747) and MrpB (Asp-121); these subunits are fused in some gram-negative species. It is possible that the MrpA, MrpB, and MrpD subunits that contain essential transmembrane acidic residues may form the ion translocation site(s) of the Mrp antiporter complex.

⁵ E-mail: kosono{at}riken.jp

This article has been cited by other articles:

				J. Torres-Bacete, P. K. Sinha, N. Castro-Guerrero, A. Matsuno-Yagi, and T. Yagi Features of Subunit NuoM (ND4) in Escherichia coli NDH-1: TOPOLOGY AND IMPLICATION OF CONSERVED GLU144 FOR COUPLING SITE 1 J. Biol. Chem., November 27, 2009; 284(48): 33062 - 33069. [Abstract] [Full Text] [PDF]