Butenyl-spinosyns, a natural example of genetic engineering of antibiotic biosynthetic genes.
Spinosyns, a novel class of insect active macrolides produced by Saccharopolyspora spinosa, are used for insect control in a number of commercial crops. Recently, a new class of spinosyns was discovered from S. pogona NRRL 30141. The butenyl-spinosyns, also called pogonins, are very similar to spinosyns, differing in the length of the side chain at C-21 and in the variety of novel minor factors. The butenyl-spinosyn biosynthetic genes (bus) were cloned on four cosmids covering a contiguous 110-kb region of the NRRL 30141 chromosome. Their function in butenyl-spinosyn biosynthesis was confirmed by a loss-of-function deletion, and subsequent complementation by cloned genes. The coding sequences of the butenyl-spinosyn biosynthetic genes and the spinosyn biosynthetic genes from S. spinosa were highly conserved. In particular, the PKS-coding genes from S. spinosa and S. pogona have 91-94% nucleic acid identity, with one notable exception. The butenyl-spinosyn gene sequence codes for one additional PKS module, which is responsible for the additional two carbons in the C-21 tail. The DNA sequence of spinosyn genes in this region suggested that the S. spinosa spnA gene could have been the result of an in-frame deletion of the S. pogona busA gene. Therefore, the butenyl-spinosyn genes represent the putative parental gene structure that was naturally engineered by deletion to create the spinosyn genes.
Hahn
Donald R
DR
Discovery Research, LLC, Dow AgroSciences, 9330 Zionsville Road., Indianapolis, IN, 46268-1054, USA.drhahn@dow.com
Gustafson
Gary
G
Waldron
Clive
C
Bullard
Brian
B
Jackson
James D
JD
Mitchell
Jon
J
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003360:Cosmids; D017353:Gene Deletion; D015723:Gene Library; D005818:Genetic Engineering / Q000379:methods*; D018942:Macrolides / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D048630:Polyketide Synthases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016930:Saccharopolyspora / Q000201:enzymology* / Q000235:genetics; D017422:Sequence Analysis, DNA
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D018942:Macrolides; C114883:spinosyn A; D048630:Polyketide Synthases