Identification of 5-Fluoro-5-Deoxy-Ribulose as a Shunt Fluorometabolite in Streptomyces sp. MA37

Funding: This study was funded by an IBioIC PhD studentship (L.W.), a Leverhulme Trust Research Project (H.D. and M.H.T., project no. RPG-2014-418), a Leverhulme Trust–Royal Society Africa award (K.K. and H.D., AA090088), the jointly funded UK Medical Research Council–UK Department for International Development (MRC/DFID) concordat agreement African Research Leaders Award (K.K. and H.D., MR/S00520X/1), and the Royal Society–NSFC Newton Mobility Grant Award (IEC\NSFC\170617 to H.D.).Peer reviewedPublisher PD

An unusual metal-bound 4-fluorothreonine transaldolase from Streptomyces sp. MA37 catalyses promiscuous transaldol reactions

Open Access via the Springer Compact Agreement. This study was funded by IBioIC PhD studentship (LW), Leverhulme Trust Research Project (HD and MHT, project No. RPG-2014-418), The Elphinstone Scholarship of University of Aberdeen (QF), Leverhulme Trust-Royal Society Africa award (KK and HD, AA090088) and the jointly funded UK Medical Research Council – UK Department for International Development (MRC/DFID) Concordat agreement African Research Leaders Award (KK and HD, MR/S00520X/1), Biotechnology and Biological Sciences Research Council UK (HD and SW, BB/P00380X/1) and National Natural Science Foundation of China (31,570,033, 31,811,530,299, and 31,870,035 to YY), and the Royal Society-NSFC Newton Mobility Grant Award (IEC\NSFC\170,617 to HD and YY).Peer reviewedPublisher PD

Targeted Dereplication of Microbial Natural Products by High-Resolution MS and Predicted LC Retention Time

A new strategy for the identification of known compounds in Streptomyces extracts that can be applied in the discovery of natural products is presented. The strategy incorporates screening a database of 5555 natural products including 5098 structures from Streptomyces sp., using a high-throughput LCMS data processing algorithm that utilizes HRMS data and predicted LC retention times (tR) as filters for rapid identification of known compounds in the natural product extract. The database, named StrepDB, contains for each compound the structure, molecular formula, molecular mass, and predicted LC retention time. All identified compounds are annotated and color coded for easier visualization. It is an indirect approach to quickly assess masses (which are not annotated) that may potentially lead to the discovery of new or novel structures. In addition, a spectral database named MbcDB was generated using the ACD/Spectrus DB Platform. MbcDB contains 665 natural products, each with structure, experimental HRESIMS, MS/MS, UV, and NMR spectra. StrepDB was used to screen a mutant Streptomyces albus extract, which led to the identification and isolation of two new compounds, legonmaleimides A and B, the structures of which were elucidated with the aid of MbcDB and spectroscopic techniques. The structures were confirmed by computer-assisted structure elucidation (CASE) methods using ACD/Structure Elucidator Suite. The developed methodology suggests a pipeline approach to the dereplication of extracts and discovery of novel natural products

Immunoregulatory Protein Profiles of Necrotizing Enterocolitis versus Spontaneous Intestinal Perforation in Preterm Infants

Necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP) are the most common acute surgical emergencies associated with high morbidity and mortality in preterm infants. We aimed to compare the profiles of immunoregulatory proteins and identify novel mediators in plasma of NEC and SIP infants. We also investigated the expression of target genes in resected intestinal tissues and an enterocyte cell line. Using Cytokine Antibody Array assay, we reported the first comparative profiles of immunoregulatory proteins in plasma of NEC and SIP infants, and showed that dysregulated proteins belonged to functionally diversified categories, including pro- and anti-inflammation, angiogenesis, cell growth, wound healing, anti-apoptosis, cell adhesion and extracellular matrix reorganization. Validation by ELISA confirmed significantly higher concentrations of interleukin (IL)-6, angiopoietin (Ang)-2, soluble type II interleukin-1 receptor (sIL-1RII), and soluble urokinase-type plasminogen activator receptor (suPAR) in NEC infants compared with gestational age-matched control, and a lower level of an epidermal growth factor receptor, secreted form of receptor tyrosine-protein kinase ErbB3 (sErbB3), compared with SIP infants. mRNA expressions of IL1-RII and uPAR were up-regulated in resected bowel tissues from NEC infants, indicating that immunoregulation also occurred at the cellular level. In FHs-74 Int cells, Ang-2, IL1-RII and uPAR mRNA expressions were significantly induced by the combined treatment with lipopolysaccharide (LPS) and platelet activating factor (PAF). Our study provided plasmatic signatures of immunoregulatory proteins in NEC and SIP infants, and demonstrated involvement of multiple functional pathways. The magnitude of changes in these proteins was significantly more extensive in NEC infants, reflecting the different nature of injury and/or severity of inflammation. We speculate that dysregulation of IL-6, Ang-2, IL-1RII and uPAR occurred at both systemic and cellular levels, and probably mediated via LPS and endogeneous PAF signals. Such exaggerated immunologic responses may account for the high morbidity and mortality in NEC compared with SIP patients

Fluoroacetate biosynthesis from the marine-derived bacterium Streptomyces xinghaiensis NRRL B-24674

Genome sequencing identified a fluorinase gene in the marine bacterium Streptomyces xinghaiensis NRRL B-24674. Fermentation of the organism with inorganic fluoride (2 mM) demonstrated that the organism could biosynthesise fluoroacetate and that fluoroacetate production is sea-salt dependent. This is the first fluoro-metabolite producing microorganism identified from the marine environment.</p

Fluoroacetate biosynthesis from the marine-derived bacterium Streptomyces xinghaiensis NRRL B-24674

Genome sequencing identified a fluorinase gene in the marine bacterium Streptomyces xinghaiensis NRRL B-24674. Fermentation of the organism with inorganic fluoride (2 mM) demonstrated that the organism could biosynthesise fluoroacetate and that fluoroacetate production is sea-salt dependent. This is the first fluoro-metabolite producing microorganism identified from the marine environment.</p

Identification of a fluorometabolite from Streptomyces sp. MA37: (2R,3S,4S)-5-Fluoro-2,3,4-trihydroxypentanoic acid

Acknowledgements DOH thanks EPSRC and the ERC for nancial support. He also acknowledges the Royal Society for a Wolfson Merit Award. KK and HD thank the Leverhulme Trust; Royal Society Africa Award (AA090088).Peer reviewedPublisher PD

Aminoacyl chain translocation catalysed by a type II thioesterase domain in an unusual non-ribosomal peptide synthetase

Non-Ribosomal Peptide Synthetases (NRPSs) assemble a diverse range of natural products with important applications in both medicine and agriculture. They consist of several multienzyme subunits that must interact with each other in a highly controlled manner to facilitate efficient chain transfer, thus ensuring biosynthetic fidelity. Several mechanisms for chain transfer are known for NRPSs, promoting structural diversity. Herein, we report the first biochemically characterized example of a type II thioesterase (TEII) domain capable of catalysing aminoacyl chain transfer between thiolation (T) domains on two separate NRPS subunits responsible for installation of a dehydrobutyrine moiety. Biochemical dissection of this process reveals the central role of the TEII-catalysed chain translocation event and expands the enzymatic scope of TEII domains beyond canonical (amino)acyl chain hydrolysis. The apparent co-evolution of the TEII domain with the NRPS subunits highlights a unique feature of this enzymatic cassette, which will undoubtedly find utility in biosynthetic engineering efforts