[Efficient production of Erythromycin C; increasing activity of discodermolide]
I thought disco was dead. More on tweaking bacteria to produce polyketide antibiotics.
>>J Am Chem Soc. 2005 May 11;127(18):6532-3.
Toward understanding how the lactone moiety of discodermolide affects activity.
Shaw SJ, Sundermann KF, Burlingame MA, Myles DC, Freeze BS, Xian M, Brouard I, Smith AB 3rd.
Kosan Biosciences, Inc., 3832 Bay Center Place, Hayward, California 94545, and University of Pennsylvania, Department of Chemistry, Philadelphia, Pennsylvania 19104.
A series of simplified discodermolide analogues have been designed and synthesized in an attempt to understand the role of the lactone ring. These synthetic efforts have led to an unsubstituted butyrolactone 9 being generated, which shows improved activity over the natural product.<<
>>Appl Environ Microbiol. 2005 May;71(5):2539-47.
Production of the Potent Antibacterial Polyketide Erythromycin C in Escherichia coli.
Peiru S, Menzella HG, Rodriguez E, Carney J, Gramajo H.
Kosan Biosciences, Inc., 3832 Bay Center Place, Hayward, CA 94545. gramajo@kosan.com.
An Escherichia coli strain capable of producing the potent antibiotic erythromycin C (Ery C) was developed by expressing 17 new heterologous genes in a 6-deoxyerythronolide B (6dEB) producer strain. The megalomicin gene cluster was used as the source for the construction of two artificial operons that contained the genes encoding the deoxysugar biosynthetic and tailoring enzymes necessary to convert 6dEB to Ery C. The reconstructed mycarose operon contained the seven genes coding for the enzymes that convert glucose-1-phosphate (G-1-P) to TDP-l-mycarose, a 6dEB mycarosyl transferase, and a 6dEB 6-hydroxylase. The activity of the pathway was confirmed by demonstrating conversion of exogenous 6dEB to 3-O-alpha-mycarosylerythronolide B (MEB). The reconstructed desosamine operon contained the six genes necessary to convert TDP-4-keto-6-deoxyglucose, an intermediate formed in the mycarose pathway, to TDP-d-desosamine, a desosamine transferase, a 6dEB 12-hydroxylase, and the rRNA methyltransferase ErmE; the last was required to confer resistance to the host cell upon production of mature macrolide antibiotics. The activity of this pathway was demonstrated by conversion of MEB to Ery C. When the mycarose and desosamine operons were expressed in an E. coli strain engineered to synthesize 6dEB, Ery C and Ery D were produced. The successful production of Ery C in E. coli shows the potentiality of this model microorganism to synthesize novel 6-deoxysugars and to produce bioactive glycosylated compounds and also establishes the basis for the future use of E. coli both in the production of new glycosylated polyketides and for the generation of novel bioactive compounds through combinatorial biosynthesis.<<
Cheers, Tuck |
