Phaseolotoxin Biosynthesis: Molecular Mechanisms of Thermoregulation
Abstract
The production phaseolotoxin (PT) and PT-resistant ornithine carbamoyl-transferase (encoded by argK of Pseudomonas syringae pv. phaseolicola are thermoregulated; both are produced at 1 18 C, but neither is produced at 30 C. At 30 C (but not at 18 C) the bacterium produces a DNA-binding protein that binds (in vitro) to sites in the upstream region of argK. Our hypothesis is that this protein is a transcription factor (TP) which negatively regulates argK and PT genes. The main objectives of this grant were to obtain complete sequences of the genes harbored by the PT gene cluster and to characterize them; and secondly, to purify the TP and clone and sequence the gene that encodes it. We have sequenced and characterized PT gene loci, phtH, phtG, phtF, phtD, phtC and most of phtB (total sequence, 16, 163-bp). Most of the genes in these loci show no homology to any genes in the databases. phtF the only gene in phtF locus harbors a DNA-binding motif. We have purified TP, and obtained its N' terminal amino acid sequence on which was based the oligonucleotide probe used in screening of the genomic library of P. s. pvphaseolicola The screening yielded a clone which harbored a gene encoding the TP. It's sequence showed 54% identity to a DNA-binding protein from E.coli.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 20, 2001
- Accession Number
- ADA387327
Entities
People
- Suresh S. Patil
Organizations
- University of Hawaiʻi System