RESUMO
Rhodobacter sphaeroides is a metabolically diverse photosynthetic alphaproteobacterium found ubiquitously in soil and freshwater habitats. Here we present the annotated genome sequence of R. sphaeroides WS8N.
Assuntos
Água Doce/microbiologia , Genoma Bacteriano , Rhodobacter sphaeroides/genética , Sequência de Bases , Dados de Sequência Molecular , Rhodobacter sphaeroides/isolamento & purificaçãoRESUMO
We have developed a stable isopropyl-beta-d-thiogalactopyranoside (IPTG)-inducible-expression plasmid, pIND4, which allows graduated levels of protein expression in the alphaproteobacteria Rhodobacter sphaeroides and Paracoccus denitrificans. pIND4 confers kanamycin resistance and combines the stable replicon of pMG160 with the lacI(q) gene from pYanni3 and the lac promoter, P(A1/04/03), from pJBA24.
Assuntos
Paracoccus denitrificans/genética , Plasmídeos/genética , Rhodobacter sphaeroides/genética , Mapeamento Cromossômico , Expressão Gênica/efeitos dos fármacos , Genes Bacterianos/efeitos dos fármacos , Vetores Genéticos , Isopropiltiogalactosídeo/farmacologia , Resistência a Canamicina/genética , Óperon Lac , Dados de Sequência Molecular , Paracoccus denitrificans/efeitos dos fármacos , Regiões Promotoras Genéticas , Replicon , Rhodobacter sphaeroides/efeitos dos fármacosRESUMO
The Escherichia coli two-component chemosensory pathway has been extensively studied, and its response regulator, CheY, has become a paradigm for response regulators. However, unlike E. coli, most chemotactic nonenteric bacteria have multiple CheY homologues. The roles and cellular localization of the CheYs in Rhodobacter sphaeroides were determined. Only two CheYs were required for chemotaxis, CheY(6) and either CheY(3) or CheY(4). These CheYs were partially localized to either of the two chemotaxis signaling clusters, with the remaining protein delocalized. Interestingly, mutation of the CheY(6) phosphorylatable aspartate to asparagine produced a stopped motor, caused by phosphorylation on alternative site Ser-83 by CheA. Extensive mutagenesis of E. coli CheY has identified a number of activating mutations, which have been extrapolated to other response regulators (D13K, Y106W, and I95V). Analogous mutations in R. sphaeroides CheYs did not cause activation. These results suggest that although the R. sphaeroides and E. coli CheYs are similar in that they require phosphorylation for activation, they may differ in both the nature of the phosphorylation-induced conformational change and their subsequent interactions with the flagellar motor. Caution should therefore be used when projecting from E. coli CheY onto novel response regulators.
