Biogenesis of T Pili in Agrobacterium tumefaciens Requires Precise VirB2 Propilin Cleavage and Cyclization |
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| Authors: | Erh-Min Lai Ralf Eisenbrandt Markus Kalkum Erich Lanka Clarence I. Kado |
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| Affiliation: | Davis Crown Gall Group, University of California, Davis, California 95616, USA. |
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| Abstract: | 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. |
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