Deciphering the Aldolase Function of STM3780 from a Bovine Enteric Infection-Related Gene Cluster in Salmonella enterica Serotype Typhimurium.
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Non-typhoidal Salmonella are capable of colonizing livestock and humans, where they can progressively cause disease. Previously, a library of targeted single-gene deletion mutants of Salmonella enterica serotype Typhimurium was inoculated to ligated ileal loops in calves to identify genes under selection. Of those genes identified, a cluster of genes is related to carbohydrate metabolism and transportation. It is proposed that an incoming carbohydrate is first phosphorylated by a phosphoenolpyruvate-dependent phosphotransferase system. The metabolite is further phosphorylated by the kinase STM3781 and then cleaved by the aldolase STM3780. STM3780 is functionally annotated as a class II fructose-bisphosphate aldolase. The aldolase was purified to homogeneity, and its aldol condensation activity with a range of aldehydes was determined. In the condensation reaction, STM3780 was shown to catalyze the abstraction of the pro-S hydrogen from C3 of dihydroxyacetone and subsequent formation of a carbon-carbon bond with S stereochemistry at C3 and R stereochemistry at C4. The best aldehyde substrate was identified as l-threouronate. Surprisingly, STM3780 was also shown to catalyze the condensation of two molecules of dihydroxyacetone phosphate to form the branched carbohydrate dendroketose bisphosphate.
author list (cited authors)
Zhi, Y., Xiang, D. F., Narindoshvili, T., Andrews-Polymenis, H., & Raushel, F. M.
complete list of authors
Zhi, Yuan||Xiang, Dao Feng||Narindoshvili, Tamari||Andrews-Polymenis, Helene||Raushel, Frank M