Identification of homologues to the pathogenicity factor Pat-1, a putative serine protease of Clavibacter michiganensis subsp. michiganensis.
Hybridization of Clavibacter michiganensis subsp. michiganensis total DNA against the pathogenicity gene pat-1 indicated the presence of pat-1 homologous nucleotide sequences on the chromosome and on plasmid pCM2. Isolation of the corresponding DNA fragments and nucleotide sequence determination showed that there are three pat-1 homologous genes: chpA (chromosome) and phpA and phpB (plasmid pCM2). The gene products share common characteristics, i.e. a signal sequence for Sec-dependent secretion, a serine protease motif, and six cysteine residues at conserved positions. Gene chpA located on the chromosome is a pseudogene since it contains a translational stop codon after 97 of 280 amino acids. In contrast to pat-1, cloning of the plasmid encoded homologs phpA and phpB into the avirulent plasmid free Cmm strain CMM100 did not result in a virulent phenotype. So far, no proteolytic activity could be demonstrated for Pat-1, however, site specific mutagenesis of pat-1 showed that the serine residue in the motif GDSGG is required for the virulent phenotype of pat-1 and thus Pat-1 could be a functional protease.
Burger
Annette
A
Biology, Microbiology/Genetechnology, University of Bielefeld, Universitätsstr. 25, D-33615 Bielefeld, Germany.
Gräfen
Ines
I
Engemann
Jutta
J
Niermann
Erik
E
Pieper
Martina
M
Kirchner
Oliver
O
Gartemann
Karl-Heinz
KH
Eichenlaub
Rudolf
R
D000192:Actinomycetales / Q000201:enzymology* / Q000235:genetics* / Q000472:pathogenicity; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D002876:Chromosomes, Bacterial / Q000235:genetics; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010957:Plasmids / Q000235:genetics; D021382:Protein Sorting Signals / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000235:genetics*; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D021382:Protein Sorting Signals; C075180:PatA protein, Anabaena; D012697:Serine Endopeptidases