‘Streptomyces nanchangensis’, a producer of the insecticidal polyether antibiotic nanchangmycin and the antiparasitic macrolide meilingmycin, contains multiple polyketide gene clusters

Abstract

Several independent gene clusters containing varying lengths of type I polyketide synthase genes were isolated from ' Streptomyces nanchangensis ' NS3226, a producer of nanchangmycin and meilingmycin. The former is a polyether compound similar to dianemycin and the latter is a macrolide compound similar to milbemycin, which shares the same macrolide ring as avermectin but has different side groups. Clusters A-H spanned about 133, 132, 104, 174, 122, 54, 37 and 59 kb, respectively. Two systems were developed for functional analysis of the gene clusters by gene disruption or replacement. (1) Streptomyces phage φC31 and its derived vectors can infect and lysogenize this strain. (2) pSET152, an Escherichia coli plasmid with φC31 attP site, and pHZ1358, a Streptomyces-Escherichia coli shuttle cosmid vector, both carrying oriT from RP4, can be mobilized from E. coli into NS3226 by conjugation. pHZ1358 was shown to be generally useful for generating mutant strains by gene disruption and replacement in NS3226 as well as in several other Streptomyces strains. A region in cluster A (" 133 kb) seemed to be involved in nanchangmycin production because replacement of several DNA fragments in this region by an apramycin resistance gene [aac3(IV)] gave rise to nanchangmycin non-producing mutants.

The pleitropic regulator AdpAch is required for natamycin biosynthesis and morphological differentiation in Streptomyces chattanoogensis

“…To construct an in-frame deletion mutant of adpA ch , a 7 kb HindIII-XbaI fragment from pMRD58 was cloned into the corresponding sites of plasmid pJTU870 (L. Bai, Jiaotong University, Shanghai, China, unpublished results), which is a derivative of pHZ1358 (Sun et al, 2002). The resulting plasmid pMRD73 was introduced into E. coli BW25113 carrying pIJ790.…”

Novel compounds produced by Streptomyces lydicus NRRL 2433 engineered mutants altered in the biosynthesis of streptolydigin

“…However, after inactivation of streptolydigin biosynthesis genes some common intermediates can be derived for the production of these compounds, being their production clearly detected. This phenomenon has been described in other systems such as the increase of nanchangmycin production by Streptomyces nanchangensis when a different biosynthesis cluster was inactivated, 40 or actinorhodin production by Streptomyces coelicolor after decreasing undecylprodigiosin yields. 41 A possible christolane pathway could be the condensation of 3-aminoisobutyric and 4-hydroxybenzoic acids or 3-hydroxyisobutyric and 4-aminobenzoic acids through the activity of a phenazine PhzF-like condensing enzyme 42 or a C-1027 SgcD5-like amide bond-forming enzyme 43 to generate christolane C. This compound might be then hydroxylated to generate christolane B or chlorinated leading to christolane A.…”

Cloning of Separate Meilingmycin Biosynthesis Gene Clusters by Use of Acyltransferase-Ketoreductase Didomain PCR Amplification

“…HPLC analysis of the fermentation broth of S. nanchangensis NS3226 identified five components of meilingmycins with similar UV absorbance, including the previously characterized meilingmycin A (Fig. 1A) (31). From a 12-liter liquid culture of the wild-type NS3226, meilingmycins A (12…”

“…Meilingmycin A, a 16-membered macrolide and identical to milbemycin ␣11, is the major product of Streptomyces nanchangensis (31). It has aglycone similar to and anthelmintic activity comparable to those of avermectins (3).…”