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156 PROCEEDINGS OF INTERNATIONAL SCIENTIFIC CONFERENCE ON APPLIED BIOTECHNOLOGY4. DISCUSSIONNormally, the sugar genes are located together in a gene cluster and responsibility for the biosynthesis of a sugar moiety, but in this case ncsS53 like galE separately located in other gene cluster belong to the genes encoding enzyme involved in the biosynthesis of extracellular polysaccharide [15], therefore ncsS53 product can be involved not only in secondary metabolite biosynthesis as deoxysugar, but also in the primary metabolite biosynthesis. The substrates for ncs53 can be UDP-glucose which is conversed to UDP-galactose, the essential component of polysaccharide membrane [16]. Although, ncsS53 shows a high homology with TDP-glucose-4.6-dehydratase also, ncsS53 is frank to the GDP-mannose synthase (ncsS52). it is hypothesized that the suitable substrates for ncsS53 therefore can be GDPmannose or TDP-glucose [17] which are the precursors for 2-methyl-fucosamine biosynthetic pathway presenting as crucial structure in the PKS compound and cell wall synthesis. Interestingly, the mechanisms of 4-epimeration is different from 4,6-dehydratase, but in both cases, NAD+ is needed as cofactor in the enzyme reaction. 5. CONCLUSIONSTo investigate the function of ncsS53 we have cloned and homologous expressed this gene in E.coli BLD3 For the further characterization, in vitro enzyme assay should be carried out to verify the enzyme function.Conflicts of Interest: The authors declare no conflict of interest. REFERENCES1. Nicolaou K. C.; Adrian L. Smith. The Enediyne Antibiotics 2007, Modern Acetylene Chemistry.