Screening, Identifying and Function Analysis of Polyketide Synthase I Domains from Soil and Seawater of Yangshan Harbor

Abstract:

To directly access typeⅠpolyketide synthases (PKS ) gene diversity from soil and seawater, a set of degenerate oligonucleotide primers were designed to amplify the ketosynthase fragments (KSs) belong to the PKS Ⅰ genes from the soil and the seawater DNA samples obtained from the Yangshan Harbor (Shanghai, China). All the unique 23 fragments (ranged from 630 bp to 690 bp after cutting off the primer and vector sequences) obtained were belonging to the conserved KS domains in PKS Ⅰ genes. Among them 19 fragments were amplified from soil (DQ640993, DQ640997, DQ641926, DQ641927, and DQ673137~DQ673151) and 4 from the seawater (DQ673151 and EF554859~EF554861). The predicated amino acid sequences showed 45% to 85% identifies to the known KSs genes in the GenBank. Phylogenetic analysis showed that 14 of them belonged to the normal KS domains that catalyzed the condensation of the acyl groups and the other 9 KS fragments belonged to the hybrid PKS/NRPS groups. Several KS fragments were endowed with some distinct characters that could be used in the following studies.