Proline-Rich Peptide from the Coral Pathogen Vibrio shiloi That Inhibits Photosynthesis of Zooxanthellae
AUTOR(ES)
Banin, Ehud
FONTE
American Society for Microbiology
RESUMO
The coral-bleaching bacterium Vibrio shiloi biosynthesizes and secretes an extracellular peptide, referred to as toxin P, which inhibits photosynthesis of coral symbiotic algae (zooxanthellae). Toxin P was produced during the stationary phase when the bacterium was grown on peptone or Casamino Acids media at 29°C. Glycerol inhibited the production of toxin P. Toxin P was purified to homogeneity, yielding the following 12-residue peptide: PYPVYAPPPVVP (molecular weight, 1,295.54). The structure of toxin P was confirmed by chemical synthesis. In the presence of 12.5 mM NH4Cl, pure natural or synthetic toxin P (10 μM) caused a 64% decrease in the photosynthetic quantum yield of zooxanthellae within 5 min. The inhibition was proportional to the toxin P concentration. Toxin P bound avidly to zooxanthellae, such that subsequent addition of NH4Cl resulted in rapid inhibition of photosynthesis. When zooxanthellae were incubated in the presence of NH4Cl and toxin P, there was a rapid decrease in the pH (pH 7.8 to 7.2) of the bulk liquid, suggesting that toxin P facilitates transport of NH3 into the cell. It is known that uptake of NH3 into cells can destroy the pH gradient and block photosynthesis. This mode of action of toxin P can help explain the mechanism of coral bleaching by V. shiloi.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=92766Documentos Relacionados
- PR-39, a proline-rich antibacterial peptide that inhibits phagocyte NADPH oxidase activity by binding to Src homology 3 domains of p47 phox.
- Genome-Wide Transcriptional Profiling of the Escherichia coli Response to a Proline-Rich Antimicrobial Peptide
- Patterns of soybean proline-rich protein gene expression.
- Syndecans, cell surface heparan sulfate proteoglycans, are induced by a proline-rich antimicrobial peptide from wounds.
- Clones from the human gene complex coding for salivary proline-rich proteins.