Synthesis of a Contiguous 32-Kb Polyketide Synthase Gene Cluster
Total synthesis of long DNA sequences: Synthesis of a contiguous 32-kb polyketide synthase gene cluster Sarah J. Kodumal, Kedar G. Patel, Ralph Reid, Hugo G. Menzella, Mark Welch, and Daniel V. Santi* Kosan Biosciences, Inc., 3832 Bay Center Place, Hayward, CA 94545 Communicated by Robert M. Stroud, University of California, San Francisco, CA, September 17, 2004 (received for review July 19, 2004) To exploit the huge potential of whole-genome sequence infor- Our efforts to this end stemmed from a desire to develop mation, the ability to efficiently synthesize long, accurate DNA heterologous expression of large polyketide synthase (PKS) sequences is becoming increasingly important. An approach pro- genes in Escherichia coli. Type I modular PKS genes encode the posed toward this end involves the synthesis of Ϸ5-kb segments of giant enzymes (among the largest proteins known) that synthe- DNA, followed by their assembly into longer sequences by con- size polyketide natural products such as erythromycin, epothi- ventional cloning methods [Smith, H. O., Hutchinson, C. A., III, lone, and tacrolimus (12). These genes reside within the high Pfannkoch, C. & Venter, J. C. (2003) Proc. Natl. Acad. Sci. USA 100, GϩC genomes of the actinomycete and myxobacterial groups of 15440–15445]. The major current impediment to the success of this prokaryotes and encode proteins with multiple sets, or modules, tactic is the difficulty of building the Ϸ5-kb components accurately, of active sites (domains). Each module catalyzes the assembly of efficiently, and rapidly from short synthetic oligonucleotide build- a specific two-carbon-unit component of the polyketide product. ing blocks.
[Show full text]