Method to produce novel polyketides

Abstract

Modified PKS gene clusters which produce novel polyketides in an efficient system in a host cell or in a cell free extract are described.

1 . A modified modular polyketide synthase (PKS) comprising at least two modules, wherein said PKS has been modified to prevent its utilization of the native starter unit for said modular PKS.  
     
     
         2 . The modified PKS of    claim 1    wherein the ketosynthase (KS) catalytic domain of module 1 has been inactivated.  
     
     
         3 . The modified PKS of    claim 1    wherein said modules are modules of the DEBS PKS.  
     
     
         4 . The modified of PKS of    claim 2    wherein said modules are modules of the DEBS PKS.  
     
     
         5 . The modified PKS of    claim 1    which is a complete PKS.  
     
     
         6 . A PKS gene cluster which encodes a modified PKS wherein said modified PKS has been modified to prevent its utilization of the native starter unit for said modular PKS.  
     
     
         7 . The gene cluster of    claim 6    wherein the ketosynthase (KS) catalytic domain of module 1 has been inactivated.  
     
     
         8 . The gene cluster of    claim 6    wherein said modules are modules of the DEBS PKS.  
     
     
         9 . The gene cluster of    claim 7    wherein said modules are modules of the DEBS PKS.  
     
     
         10 . The gene cluster of    claim 6    which encodes a complete PKS.  
     
     
         11 . A recombinant host cell modified to contain the gene cluster of    claim 6   .  
     
     
         12 . The host cell of    claim 10    which is a Streptomyces.  
     
     
         13 . The host cell of    claim 10    which is free of any endogenous PKS activity.  
     
     
         14 . A method to prepare a polyketide, which method comprises providing a thioester diketide substrate for the modified PKS of    claim 1   .  
     
     
         15 . The method of    claim 14    which is conducted in a host cell.  
     
     
         16 . The method of    claim 14    which is conducted in a cell free system.  
     
     
         17 . A novel polyketide which has the structure shown as formula 6, 7 or 8 in FIG. 2.