Next-generation sequencing has become the most widely used sequencing technology in genomics research, but it has inherent drawbacks when dealing with high-GC content genomes. Recently, single-molecule real-time sequencing technology (SMRT) was introduced as a third-generation sequencing strategy to compensate for this drawback. Here, we report that the unbiased and longer read length of SMRT sequencing markedly improved genome assembly with high GC content via gap filling and repeat resolution.
Many readers of this journal will need no introduction to the bacterial genus Streptomyces, which includes several hundred species, many of which produce biotechnologically useful secondary metabolites. The last 2 years have seen numerous publications describing Streptomyces genome sequences (Table?1), mostly as short genome announcements restricted to just 500 words and therefore allowing little description and analysis. Our aim in this current manuscript is to survey these recent publications and to dig a little deeper where appropriate. The genus Streptomyces is now one of the most highly sequenced, with 19 finished genomic sequences (Table?2) and a further 125 draft assemblies…
We report the identification of the biosynthetic gene cluster for the unusual antibiotic anthracimycin (atc) from the marine derived producer strain Streptomyces sp. T676 isolated off St. John’s Island, Singapore. The 53?253 bps atc locus includes a trans-acyltransferase (trans-AT) polyketide synthase (PKS), and heterologous expression in Streptomyces coelicolor resulted in anthracimycin production. Analysis of the atc cluster revealed that anthracimycin is likely generated by four PKS gene products AtcC-AtcF without involvement of post-PKS tailoring enzymes, and a biosynthetic pathway is proposed. The availability of the atc cluster provides a basis for investigating the biosynthesis of anthracimycin and its subsequent bioengineering…
A genome sequence assembly represents a model of a genome. This article explores some tools and methods for assessing the quality of an assembly, using publicly available data for Streptomyces species as the example. There is great variability in quality of assemblies deposited in GenBank. Only in a small minority of these assemblies are the raw data available, enabling full appraisal of the assembly quality. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.
Like many fields of the biosciences, actinomycete natural products research has been revolutionised by next-generation DNA sequencing (NGS). Hundreds of new genome sequences from actinobacteria are made public every year, many of them as a result of projects aimed at identifying new natural products and their biosynthetic pathways through genome mining. Advances in these technologies in the last five years have meant not only a reduction in the cost of whole genome sequencing, but also a substantial increase in the quality of the data, having moved from obtaining a draft genome sequence comprised of several hundred short contigs, sometimes of…
The Carbohydrate Active Enzyme (CAZy) database indicates that glycoside hydrolase family 55 (GH55) contains both endo- and exo-ß-1,3-glucanases. The founding structure in the GH55 is PcLam55A from the white rot fungus Phanerochaete chrysosporium (Ishida, T., Fushinobu, S., Kawai, R., Kitaoka, M., Igarashi, K., and Samejima, M. (2009) Crystal structure of glycoside hydrolase family 55 ß-1,3-glucanase from the basidiomycete Phanerochaete chrysosporium. J. Biol. Chem. 284, 10100-10109). Here, we present high resolution crystal structures of bacterial SacteLam55A from the highly cellulolytic Streptomyces sp. SirexAA-E with bound substrates and product. These structures, along with mutagenesis and kinetic studies, implicate Glu-502 as the catalytic…
Streptomyces leeuwenhoekii, isolated from the hyperarid Atacama Desert, produces the new ansamycin-like compounds chaxamycins A to D, which possess potent antibacterial activity and moderate antiproliferative activity. We report the development of genetic tools to manipulate S. leeuwenhoekii and the identification and partial characterization of the 80.2-kb chaxamycin biosynthesis gene cluster, which was achieved by both mutational analysis in the natural producer and heterologous expression in Streptomyces coelicolor A3(2) strain M1152. Restoration of chaxamycin production in a nonproducing ?cxmK mutant (cxmK encodes 3-amino-5-hydroxybenzoic acid [AHBA] synthase) was achieved by supplementing the growth medium with AHBA, suggesting that mutasynthesis may be a…
Streptomyces sp. strain Wb2n-11, isolated from native desert soil, exhibited broad-spectrum antagonism against plant pathogenic fungi, bacteria, and nematodes. The 8.2-Mb draft genome reveals genes putatively responsible for its promising biocontrol activity and genes which enable the soil bacterium to directly interact beneficially with plants. Copyright © 2015 Köberl et al.
The genome sequence of the first Streptomyces species isolated from the Brazilian Caatinga is reported here. Genes related to environmental stress tolerance were prevalent and included many secondary metabolic gene clusters. Copyright © 2015 Santos et al.
Streptomyces sp. strain CFMR 7, which naturally degrades rubber, was isolated from a rubber plantation. Whole genome sequencing and assembly resulted in 2 contigs with total genome size of 8.248 Mb. Two latex clearing protein (lcp) genes which are responsible for rubber degrading activities were identified. Copyright © 2015 Elsevier B.V. All rights reserved.
Streptomyces ambofaciens ATCC23877 is a soil bacterium industrially exploited for the production of the macrolide spiramycin which is used in human medicine as an antibacterial and anti-toxoplasmosis chemical. Its genome consists of a 8.3Mbp linear chromosome and a 89kb circular plasmid. The complete genome sequence reported here will enable us to investigate Streptomyces genome evolution and to discover new secondary metabolites with potential applications notably in human medicine. Copyright © 2015 Elsevier B.V. All rights reserved.
The cyclizidine biosynthetic gene cluster was identified from Streptomyces NCIB 11649, which revealed the polyketide biosynthetic machinery for cyclizidine alkaloid biosynthesis. Both in vivo mutagenesis study and in vitro biochemical analysis provided insight into the timing and mechanism of the biosynthetic enzymes that produce cyclizidine-type indolizidine alkaloids.
Actinomycetes are a major source of antimicrobials, anticancer compounds, and other medically important products, and their genomes harbor extensive biosynthetic potential. Major challenges in the screening of these microorganisms are to activate the expression of cryptic biosynthetic gene clusters and the development of technologies for efficient dereplication of known molecules. Here we report the identification of a previously unidentified isatin-type antibiotic produced by Streptomyces sp. MBT28, following a strategy based on NMR-based metabolomics combined with the introduction of streptomycin resistance in the producer strain. NMR-guided isolation by tracking the target proton signal resulted in the characterization of 7-prenylisatin (1) with…
Here, we present the complete genome sequence of Streptomyces sp. strain CCM_MD2014 (phylum Actinobacteria), isolated from surface soil in Woods Hole, MA. Its single linear chromosome of 8,274,043 bp in length has a 72.13% G+C content and contains 6,948 coding sequences. Copyright © 2015 Mariita et al.
Streptomyces sp. strain NTK 937 is the producer of the benzoxazole antibiotic caboxamycin, which has been shown to exert inhibitory activity against Gram-positive bacteria, cytotoxic activity against several human tumor cell lines, and inhibition of the enzyme phosphodiesterase. In this genome announcement, we present a draft genome sequence of Streptomyces sp. NTK 937 in which we identified at least 35 putative secondary metabolite biosynthetic gene clusters. Copyright © 2014 Olano et al.