REGULATION AND STRUCTURE OF THE AMS-REGION INVOLVED IN EXOPOLYSACCHARIDE SYNTHESIS OF ERWINIA AMYLOVORA

For protection against recognition by plant defence mechanisms, Erwinia amylovora synthesizes the capsular EPS amylovoran.
The repeating unit of amylovoran consists of one glucuronic acid and four galactose residues.
Synthesis continues into the stationary growth phase and depends on regulator proteins and environmental conditions.
The rcsB gene, involved in activation of amylovoran synthesis, was isolated by PCR amplification and its sequence was determined.
It is highly homologous to similar genes of other bacteria.
Most genes for amylovoran synthesis are transcribed from an operonic structure as a 16 kb mRNA. Analysis of the possible gene functions has been attempted by homology search in a protein-sequence data library.
The predicted amino acid sequence of AmsG is homologous to galactosyl-1-phosphate undecaprenyl-phosphate transferases.
AmsB and AmsD are similar to other glycosyl transferases, and AmsH to BexD. A significant homology to mammalian phosphatases was observed for Amsl.
AmsA shows characteristic motifs for ATP-binding and, similar to AmsH and AmsL, helical transmembrane segments.
AmsF carries a secretory signal sequence in the N-terminus and could be involved in periplasmic processing of the repeating units.

VII International Workshop on Fire Blight

P. Bugert, S. Bereswill, K. Geider

https://doi.org/10.17660/ActaHortic.1996.411.54