Abstract
Specialized lambda-transducing phages that carry the Escherichia coli genes ptsH, ptsI, crr, cysM, and cysA have been isolated, and the genes were subcloned in plasmid pBR322. Subcloning and restriction mapping data gave the following clockwise order of genes located at about 52 min on the E. coli genetic map: lig, cysK, ptsH, ptsI, crr, cysM, cysA. The nucleotide sequences of ptsH, ptsI, and crr and the corresponding flanking regions have been determined. These genes encode three cytoplasmic proteins of the phosphoenol-pyruvate:glycose phosphotransferase system: HPr, Enzyme I, and IIIGlc, respectively. The deduced amino acid sequences are consistent with amino acid composition and Edman degradation analyses obtained with the purified proteins. The calculated subunit molecular weight values (9,109 for HPr, 63,489 for Enzyme I, and 18,099 for IIIGlc) also agree well with values obtained with the proteins. Results of gamma delta-transposon insertional studies provided definitive evidence that IIIGlc is the gene product of crr, and therefore that IIIGlc plays a critical role in regulating the metabolism and uptake of certain non-PTS sugars (see accompanying papers: Mitchell, W.J., Saffen, D.W., and Roseman, S. (1987) J. Biol. Chem. 16254-16260; Misko, T.P., Mitchell, W.J., Meadow, N.D., and Roseman, S. (1987) J. Biol. Chem. 16261-16266). The gamma delta transposon studies also suggest that crr is transcribed from an independent promoter located within the ptsI gene. Putative regulatory sequence features include a catabolite gene activator protein-cAMP-binding site and two regions of 2-fold rotational symmetry adjacent to the potential promoter upstream from the HPr structural gene, several ribosome-binding sites, and a rho-independent RNA polymerase termination site downstream from crr. In addition, the ptsI gene contains two highly conserved direct repeats. The significance of these sequence features is discussed with respect to possible multiple forms of pts regulation.
Highlights
SpecializedX-transducingphages t h a tc a r r yt h e of these sequence featuresis discussed with respect to Escherichia coligenes ptsH, ptslc, rr, cysM, and cysA possible multipleforms of pts regulation
We describe the use of yd-transposon t a n t ~ . ~ TchyesK and cysMgenes of S. typhimurium have mutagenesis toanalyze the transcriptional organizatioonf the been shown to code for the isozymes 0-acetylserine sulfhyptsH,ptsl,andcrr genes
X-transducingphages carrying pts genes, a procedure that IIIGkIs Encoded by crr-In earlier studies[15], we reported would minimize exposure of the host bacteria to high copy that the PTS regulates the utilization of at least four nonnumbers of these genes
Summary
Since genetic regulation of the PTS is so critical [25], is carried on plasmidpDS40 This plasmid restores the for survival of a bacterium, it is important to determine the ability of several cysA mutants to utilize sulfate as the sole finestructuralorganizationandtranscriptionalcontrol of source of sulfur, althoughit has not been established whether regions of the bacterialchromosome coding forPTS proteins. One of the PTS is relieved by mutation of a single gene, designated thesetransducing phages, Xplig, carries a functional crr [7]; crr mutants contain low to negligible levels of the ptsH gene and a nonfunctional, 5'-terminal fragmentof ptsl. Underlying PTS regulation of the non-PTS systems and of Molecular Cloning of the crr, cysA, and cysM Genes of E. diauxic growth.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
