Identification of mdoD, an mdoG paralog which encodes a twin-arginine-dependent periplasmic protein that controls osmoregulated periplasmic glucan backbone structures.
Osmoregulated periplasmic glucans (OPGs) of Escherichia coli are anionic and highly branched oligosaccharides that accumulate in the periplasmic space in response to low osmolarity of the medium. The glucan length, ranging from 5 to 12 glucose residues, is under strict control. Two genes that form an operon, mdoGH, govern glucose backbone synthesis. The new gene mdoD, which appears to be a paralog of mdoG, was characterized in this study. Cassette inactivation of mdoD resulted in production of OPGs with a higher degree of polymerization, indicating that OpgD, the mdoD product (according to the new nomenclature), controls the glucose backbone structures. OpgD secretion depends on the Tat secretory pathway. Orthologs of the mdoG and mdoD genes are found in various proteobacteria. Most of the OpgD orthologs exhibit a Tat-dependent secretion signal, while most of the OpgG orthologs are Sec dependent.
Lequette
Yannick
Y
U.S.T.L., BAt. C9, 59655 Villeneuve d'Ascq Cedex, France. jean-pierre.bohin@univ-lille1.fr
Odberg-Ferragut
Carmen
C
Bohin
Jean-Pierre
JP
Lacroix
Jean-Marie
JM
D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005936:Glucans / Q000096:biosynthesis*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D009994:Osmolar Concentration; D019897:Periplasm / Q000378:metabolism; D033903:Periplasmic Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D029968:Escherichia coli Proteins; D005936:Glucans; C487482:MdoD protein, E coli; C089830:MdoG protein, E coli; D026901:Membrane Transport Proteins; D033903:Periplasmic Proteins; C408585:twin-arginine translocase complex, E coli