Expression of megosamine biosynthetic pathway in E. coli: Generation of megalomicin analogues

MARIANA USEGLIO; SALVADOR PEIRÚ; EDUARDO RODRÍGUEZ; HUGO GRAMAJO

Villa Carlos PAz, Córdoba, Argentina

Congreso; XLIV Reunión anual-Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Megalomicins are terapeutically important compounds which have antiparasitic, antiviral and antibacterial properties. They are produced by Micromonospora megalomicea and differ from erythromycin by the addition of a unique deoxyamino sugar, megosamine, to the C6 hydroxyl.In this work we identified the genes involved in the megalomycin pathway and validate it by the expression of the genes in Escherichia coli.  LC/MS/MS analysis of the dTDP-sugar intermediates produce by operons containing diferent sets of genes showed that production of dTDP-L-megosamine from dTDP-4-keto-6-deoxy-D-glucose require only five biosynthetic steps, the first three step are common with others TDP-sugar pathways while the last two are specific from this pathway. The validation of this pathway was demonstrated by conversion of EryC to Megalomicina A.In addition, we feed different erythromycin C analogues, erythromicin A and azithromycin to generate new compounds, 6-megosaminil-erithromycin A and 6-megosaminil-azithromycin, respectly. These results indicate a significant flexibility of proteins which are MegDI-MegDVI, involved in the L-megosamine transference to alternative macrolactone. The antiparasitic and antibacterial activity of these new compounds is being evaluated.