Biogenesis of T pili in Agrobacterium tumefaciens requires precise VirB2 propilin cleavage and cyclization.
VirB2 propilin is processed by the removal of a 47-amino-acid signal peptide to generate a 74-amino-acid peptide product in both Escherichia coli and Agrobacterium tumefaciens. The cleaved VirB2 protein is further cyclized to form the T pilin in A. tumefaciens but not in E. coli. Mutations in the signal peptidase cleavage sequence of VirB2 propilin cause the formation of aberrant T pilin and also severely attenuate virulence. No T pilus was observed in these mutants. The potential role of the exact VirB2 propilin cleavage and cyclization in T pilus biogenesis and virulence is discussed.
Lai
Erh-Min
EM
Davis Crown Gall Group, University of California, Davis, California 95616, USA.
Eisenbrandt
Ralf
R
Kalkum
Markus
M
Lanka
Erich
E
Kado
Clarence I
CI
D016960:Agrobacterium tumefaciens / Q000378:metabolism* / Q000472:pathogenicity; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D013286:Datura stramonium / Q000382:microbiology; D036781:Fimbriae Proteins; D010861:Fimbriae, Bacterial / Q000378:metabolism*; D008565:Membrane Proteins; D009154:Mutation; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D021382:Protein Sorting Signals / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism; D037521:Virulence Factors
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D008565:Membrane Proteins; D011498:Protein Precursors; D021382:Protein Sorting Signals; D011994:Recombinant Proteins; D037521:Virulence Factors; D036781:Fimbriae Proteins; D012697:Serine Endopeptidases; C026515:type I signal peptidase