Articles
NUCLEOTIDE SEQUENCE ANALYSIS OF THE ERWINIA STEWARTII CPS GENE CLUSTER FOR SYNTHESIS OF STEWARTAN AND COMPARISON TO THE ERWINIA AMYLOVORA AMS CLUSTER FOR SYNTHESIS OF AMYLOVORAN
Article number
411_49
Pages
251 – 258
Language
Abstract
Erwinia amylovora and Erwinia stewartii form related exopolysaccharide (EPS) capsules, which are the products of the ams and cps gene clusters, respectively.
The nucleotide sequence of 18.5 kb from the cps cluster was determined.
Thirteen ORFs were arranged in the order cpsA, B, I, C, D, E, F, G, H, J, K, L, and M. The predicted amino acid sequences of the CpsA, B, I, C, H, J, K, L, and M, proteins were over 59% identical (>80% similar) to the products of ams genes mapping at the same position.
Data base searches suggested functions for several gene products.
CpsA/AmsG may add galactose to the lipid carrier; CpsB/AmsH and CpsC/AmsA are membrane proteins that may be involved in export and polymerization of the repeating unit; Cpsl/Amsl have homologies to acid phosphatases; and the CpsD, E, G, and K and AmsB, C, D, E and K proteins have features of glycosyl-transferases.
CpsF, CpsH, and CpsJ did not have homology to known proteins.
CpsD, CpsF, and CpsG exhibit only 16–37% identity with AmsC, AmsE, and AmsD, respectively, whereas CpsE is 74% identical to AmsB and CpsK and AmsK are 71% identical.
These results indicate that E. stewartii and E. amylovora may use a common mechanism for EPS synthesis, which differs in three enzymes that determine repeat unit structure.
The nucleotide sequence of 18.5 kb from the cps cluster was determined.
Thirteen ORFs were arranged in the order cpsA, B, I, C, D, E, F, G, H, J, K, L, and M. The predicted amino acid sequences of the CpsA, B, I, C, H, J, K, L, and M, proteins were over 59% identical (>80% similar) to the products of ams genes mapping at the same position.
Data base searches suggested functions for several gene products.
CpsA/AmsG may add galactose to the lipid carrier; CpsB/AmsH and CpsC/AmsA are membrane proteins that may be involved in export and polymerization of the repeating unit; Cpsl/Amsl have homologies to acid phosphatases; and the CpsD, E, G, and K and AmsB, C, D, E and K proteins have features of glycosyl-transferases.
CpsF, CpsH, and CpsJ did not have homology to known proteins.
CpsD, CpsF, and CpsG exhibit only 16–37% identity with AmsC, AmsE, and AmsD, respectively, whereas CpsE is 74% identical to AmsB and CpsK and AmsK are 71% identical.
These results indicate that E. stewartii and E. amylovora may use a common mechanism for EPS synthesis, which differs in three enzymes that determine repeat unit structure.
Publication
Authors
D.L. Coplin, D.R. Majerczak, P. Bugert, K. Geider
Keywords
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