Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Yersinia pestis strain KIM requires plasmid pCD1 for expression of the low calcium response, plague virulence antigen V, and virulence. We constructed Mu d1(Ap lac) insertion mutants of this plasmid which were unable to express the low calcium response. The insertions mapped to a 17-kilobase region of the plasmid. By determining the orientation of the insertions and examining beta-galactosidase production from the Mu d1 lac genes, we determined that this region contains three units of transcription, one of which is transcribed in a direction opposite the direction of transcription of the other two. Transcription of at least two of these units was induced significantly at 37 degrees C compared with 26 degrees C. Ca2+ (2.5 mM) and ATP (18 mM) had no significant effect on the level of expression of the Mu d1 lac genes of these mutants. All insertions in the region strongly reduced production of the V antigen. Insertions from each unit of transcription also reduced virulence in mice.
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PMID:Genetic analysis of the low calcium response in Yersinia pestis mu d1(Ap lac) insertion mutants. 609 9

Primarily, three operons, hmsHFRS, hmsT and hmsP, are responsible for the development of a Yersinia pestis biofilm, which is essential for blockage-dependent transmission of plague from fleas to mammals. Here, using specific antibodies, a polymeric beta-1,6-N-acetyl-d-glucosamine-like polysaccharide was detected in the extracellular matrix of hmsHFRS-dependent Y. pestis biofilm. The production of this exopolysaccharide (EPS) was controlled by diguanylate cyclase HmsT and EAL domain phosphodiesterase HmsP, acting as positive and negative regulators respectively. Cellular compartmentalization of soluble segments of Hms inner membrane proteins, including the putative glycosyltransferase domain of HmsR, the diguanylate cyclase/GGDEF domain of HmsT and the phosphodiesterase/EAL domain of HmsP, was determined by a combination of topology prediction algorithms and construction of C-terminal translational fusions with beta-galactosidase and alkaline phosphatase. Multiple interactions of Hms inner membrane proteins were detected using bacterial cAMP based two-hybrid system. Biochemical analyses confirmed some of these protein-protein interactions. Our results indicate that synthesis and regulation of the Y. pestis biofilm EPS occurs in the cytoplasm by a proposed Hms enzymatic complex.
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PMID:Insights into Yersinia pestis biofilm development: topology and co-interaction of Hms inner membrane proteins involved in exopolysaccharide production. 1827 44