Borrelidin-producing polyketide synthase and its use

Abstract

The present invention relates to the biosynthesis of polyketides and derives from the cloning of nucleic acids encoding a polyketide synthase and other associated proteins involved in the synthesis of the polyketide borrelidin. Materials and Methods including enzyme systems, nucleic acids, vectors and cells are provided for the preparation of polyketides including borrelidin and analogues and derivatives thereof. Novel polyketide molecules are also provided.

1 - 73 . (canceled) 
     
     
         74 . A host cell capable of expressing a polyketide synthase for borrelidin or a borrelidin derivative or analogue, in which a borrelidin biosynthetic gene involved in production of the borrelidin starter unit in said cell, has been deleted, disrupted, or otherwise inactivated wherein said gene is selected from the list consisting of borC, borD, borE, borF, borG, borH, borK, borL, borM, and borN. 
     
     
         75 . The host cell according to  claim 74  wherein the gene is borG. 
     
     
         76 . The host cell according to  claim 74  wherein the gene is borE. 
     
     
         77 . The host cell according to  claim 74  in which one or more borrelidin biosynthesis genes or borrelidin polyketide synthase domains or modules are additionally deleted, modified or replaced. 
     
     
         78 . The host cell according to  claim 74  which is an Actinomycete. 
     
     
         79 . The host cell according to  claim 74  which is a Streptomycete. 
     
     
         80 . The host cell according to  claim 74  wherein the host cell is selected from the group consisting of  Saccharopolyspora erythraea, Streptomyces coelicolor, Streptomyces avermitilis, Streptomyces griseofuscus, Streptomyces cinnamonensis, Micromonospora griseorubida, Streptomyces hygroscopicus, Streptomyces fradiae, Streptomyces longisporoflavus, Streptomyces lasaliensis, Streptomyces tsukubaensis, Streptomyces griseus, Streptomyces venezuelae, Streptomyces antibioticus, Streptomyces lividans, Streptomyces rimosus, Streptomyces albus, Streptomyces rochei  ATCC23956,  Streptomyces parvulus  Tü113, and  Streptomyces parvulus  Tü4055. 
     
     
         81 . A method for modifying a host cell to increase its capacity for the production of borrelidin, or a borrelidin derivative or analogue, the host cell being capable of expressing a polyketide synthase for borrelidin or said derivative or analogue, the method comprising deleting, disrupting, or otherwise inactivating a borrelidin biosynthetic gene involved in production of the borrelidin starter unit in said cell, wherein the gene is selected from the group consisting of borC, borD, borE, borF, borG, borH, borK, borL, borM and borN. 
     
     
         82 . The method according to  claim 81  wherein the gene is borG. 
     
     
         83 . The method according to  claim 81  wherein the gene is borE. 
     
     
         84 . The method of  claim 81 , wherein the gene is borG and the method additionally comprises deleting, modifying or replacing one or more borrelidin biosynthesis genes or borrelidin polyketide synthase domains or modules. 
     
     
         85 . A method for producing borrelidin, or a borrelidin derivative or analogue, said method comprising fermenting a host cell according to  claim 74  and feeding an exogenous carboxylic acid. 
     
     
         86 . The method of  claim 85  wherein the gene is borG and wherein the exogenous carboxylic acid is selected from the group consisting of trans-cyclobutane-1,2-dicarboxylic acid, 2,3-dimethylsuccinic acid, 2-methylsuccinic acid, and trans-cyclopentane-1,2-dicarboxylic acid. 
     
     
         87 . The method according to  claim 85 , further comprising the step of isolating the borrelidin, borrelidin derivative or borrelidin analogue.