PMID:8576039

Citation	Wengelnik, K, Marie, C, Russel, M and Bonas, U (1996) Expression and localization of HrpA1, a protein of Xanthomonas campestris pv. vesicatoria essential for pathogenicity and induction ofthe hypersensitive reaction. J. Bacteriol. 178:1061-9
Abstract	The hrp cluster of the pepper and tomato pathogen Xanthomonas campestris pv. vesicatoria is required for both pathogenicity on susceptible host plants and induction of the hypersensitive reaction on resistant plants. The hrpA locus is located at the left end of the 25-kb hrp region and encodes a single 64-kDa Hrp protein, HrpA1, which belongs to the PulD superfamily of proteins involved in type II and type III protein secretion. In this study, we developed a defined medium without any plant-derived molecules that induces expression of hrpA in vitro. The hrpA transcription start site was mapped in the coding region of the hrpB8 gene, which is the last gene of the hrpB operon. The inducible hrpA promoter shows no homology to known promoter elements or other hrp loci of X. campestris pv. vesicatoria. hrpA expression was shown to be independent of the hrp regulatory gene hrpX. The amino acid sequence of the HrpA1 protein is predicted to contain an N-terminal signal sequence and no further transmembrane domains and to be rich in beta-sheet stretches. Expression of HrpA1 in Escherichia coli cells causes induction of the psp operon like some of its counterparts, suggesting some commonality of function and that HrpA1 forms multimers. The protein product of hrpA1 was identified by using a specific polyclonal antibody. Cell fractionation studies demonstrated that the HrpA1 protein is localized in the outer membrane of X. campestris pv. vesicatoria. HrpA1 is the first component of the Hrp secretion system whose localization has been determined in the original organism.
Links	PubMed PMC177766
Keywords	Amino Acid Sequence; Bacterial Outer Membrane Proteins/biosynthesis; Bacterial Outer Membrane Proteins/genetics; Bacterial Outer Membrane Proteins/isolation & purification; Bacterial Proteins/biosynthesis; Base Sequence; Cell Compartmentation; Cell Fractionation; Escherichia coli/genetics; Gene Expression Regulation, Bacterial; Heat-Shock Proteins/biosynthesis; Molecular Sequence Data; Operon; Plant Diseases; Promoter Regions, Genetic; Recombinant Proteins/biosynthesis; Sequence Analysis, DNA; Transcription, Genetic; Vegetables/microbiology; Vegetables/physiology; Xanthomonas campestris/genetics; Xanthomonas campestris/pathogenicity
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
XANC5:Q3BQH9	part_of	GO:0031226: intrinsic component of plasma membrane	ECO:0000314: direct assay evidence used in manual assertion		C		Seeded From UniProt	complete
XANC5:Q3BQH9		GO:0031226: intrinsic to plasma membrane	ECO:0000314:		C		Figure 7	complete CACAO 3429

References

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