Once activated, Rrp1 directs the synthesis of cyclic dimeric GMP (c-di-GMP), which, in turn, modulates the expression and/or activity of gene products required for survival within feeding ticks. We hypothesize that the phosphorelay between Hk1 and Rrp1 is initiated by the binding of feeding-specific ligand(s) to Hk1 sensor domain D1 and/or D2. Extensive characterization of the resulting mutants revealed a dramatic phenotype whereby Hk1-deficient spirochetes are virulent in mice and able to migrate out of the bite site during feeding but are killed within the midgut following acquisition. To investigate the role of Hk1 during the enzootic cycle, we inactivated this gene in two virulent backgrounds. In addition to its REC domain, Rrp1 contains a GGDEF motif characteristic of diguanylate cyclases. Hk1 is composed of two periplasmic sensor domains (D1 and D2), followed by conserved cytoplasmic histidine kinase core, REC, and Hpt domains. The other TCS consists of a hybrid histidine kinase, Hk1, and the response regulator Rrp1. Genes within the Rrp2/RpoN/RpoS regulon function to promote tick transmission and early infection. While the contribution of Hk2 remains unclear, Rrp2 is part of a regulatory pathway involving the spirochete's alternate sigma factors, RpoN and RpoS. One is comprised of a histidine kinase, Hk2, and the response regulator Rrp2. Borrelia burgdorferi encodes only two TCS. Kropinski (Email: Phage.Canada (at) gmail.Two-component systems (TCS) are principal mechanisms by which bacteria adapt to their surroundings. Problems and suggestions: Contact - Andrew M. Kropinski, Departments of Food Science and, Pathobiology University of Guelph, Guelph, Ontario, N1G 2W1 CANADA The Bio-Web: Resources for Molecular and Cell Biologists is a non-commercial, educational site with the only purpose of facilitating access to biology-related information over the internet.ĬREATED BY: Dr. WINDOWS- & JAVA or PERL-BASED PROGRAMS- free molecular biology programsĭOWNLOADING SEQUENCES FROM GENBANK & MANIPULATING THEM IN BIOEDIT TRANSLATION (EUKARYOTIC GENES) (identification of introns and exons) TERTIARY STRUCTURE PREDICTIONS OF SACCHARIDESĬONVERT SEQUENCE(upper to low case, complement, reverse, RNA to DNA) ONLINE RESOURCES (tutorials and glossaries) - Needs work ![]() Click on the button labeled "Search," "Run" or "Submit." If in doubt use the default setting that the sites provide, but for the more adventuresome some of the sites offer the chance of modifying the search strategy. Each of these Web Sites has a box into which you can "Paste" your sequence. Each of the items in blue text is hyperlinked to a site on the Web. Prior to trying out a Web Site select the sequence and copy to clipboard. For those with no experience I have provided three sequences: (a) a DNA sequence, (b) a protein sequence, and (c) four protein sequences presented in FASTA format. The availability of online tools permits even the novice molecular biologist the opportunity to derive a considerable amount of useful nformation from nucleotide or protein sequence data. Analysis of nucleotide and protein sequence data was initially restricted to those with access to complicated mainframe or expensive desktop computer programs (for example PC/GENE, Lasergene, MacVector, Accelrys etc.).
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