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Dna-encoded library

Ju Hyoung Lim, Ho-Gun Rhie, Jeong Nam Kim
Pseudomonas fluorescens KLR101 was found to be capable of producing polyhydroxyalkanoate (PHA) using various sugars and fatty acids with carbon numbers ranging from 2 to 6. PHA granules mainly consisted of poly(3-hydroxybutyrate) homopolymer and/or poly(3-hydroxybutyrate- co -3-hydroxyvalerate) copolymer. Genomic DNA of P. fluorescens was fractionated and cloned into a lambda library, in which a 5.8-kb fragment hybridized to a heterologous phaC probe from Ralstonia eutropha was identified. In vivo expression in Klebsiella aerogenes KC2671 (pUMS), restriction mapping, Southern hybridization experiments, and sequencing data revealed that PHA biosynthesis by P...
May 11, 2018: Journal of Microbiology and Biotechnology
Dean G Brown, Jonas Boström
An analysis of 66 published clinical candidates from Journal of Medicinal Chemistry has been conducted to shed light on which lead generation strategies are most frequently employed in identifying drug candidates. The most frequent lead generation strategy (producing a drug candidate) was based on starting points derived from previously known compounds (43%) followed by random high throughput screening (29%). The remainder of approaches included focused screening, structure-based drug design (SBDD), fragment-based lead generation (FBLG) and DNA-encoded library screening (DEL)...
June 19, 2018: Journal of Medicinal Chemistry
Joshua T Atkinson, Alicia M Jones, Quan Zhou, Jonathan J Silberg
Deep mutational scanning has been used to create high-resolution DNA sequence maps that illustrate the functional consequences of large numbers of point mutations. However, this approach has not yet been applied to libraries of genes created by random circular permutation, an engineering strategy that is used to create open reading frames that express proteins with altered contact order. We describe a new method, termed circular permutation profiling with DNA sequencing (CPP-seq), which combines a one-step transposon mutagenesis protocol for creating libraries with a functional selection, deep sequencing and computational analysis to obtain unbiased insight into a protein's tolerance to circular permutation...
April 18, 2018: Nucleic Acids Research
Shamima Nasrin, Suresh Ganji, Kavita S Kakirde, Melissa R Jacob, Mei Wang, Ranga Rao Ravu, Paul A Cobine, Ikhlas A Khan, Cheng-Cang Wu, David A Mead, Xing-Cong Li, Mark R Liles
A functional metagenomic approach identified novel and diverse soil-derived DNAs encoding inhibitors to methicillin-resistant Staphylococcus aureus (MRSA). A metagenomic DNA soil library containing 19 200 recombinant Escherichia coli BAC clones with 100 Kb average insert size was screened for antibiotic activity. Twenty-seven clones inhibited MRSA, seven of which were found by LC-MS to possess modified chloramphenicol ( Cm) derivatives, including three new compounds whose structures were established as 1-acetyl-3-propanoylchloramphenicol, 1-acetyl-3-butanoylchloramphenicol, and 3-butanoyl-1-propanoylchloramphenicol...
June 13, 2018: Journal of Natural Products
Verena Kunig, Marco Potowski, Anne Gohla, Andreas Brunschweiger
DNA-encoded compound libraries are a highly attractive technology for the discovery of small molecule protein ligands. These compound collections consist of small molecules covalently connected to individual DNA sequences carrying readable information about the compound structure. DNA-tagging allows for efficient synthesis, handling and interrogation of vast numbers of chemically synthesized, drug-like compounds. They are screened on proteins by an efficient, generic assay based on Darwinian principles of selection...
June 27, 2018: Biological Chemistry
Melanie Leveridge, Chun-Wa Chung, Jeffrey W Gross, Christopher B Phelps, Darren Green
There has been much debate around the success rates of various screening strategies to identify starting points for drug discovery. Although high-throughput target-based and phenotypic screening has been the focus of this debate, techniques such as fragment screening, virtual screening, and DNA-encoded library screening are also increasingly reported as a source of new chemical equity. Here, we provide examples in which integration of more than one screening approach has improved the campaign outcome and discuss how strengths and weaknesses of various methods can be used to build a complementary toolbox of approaches, giving researchers the greatest probability of successfully identifying leads...
June 1, 2018: SLAS Discovery
Ying Wang, Pengjie Hu, Honghua Li, Yanling Wang, Liang-Kun Long, Kuan Li, Xiaoling Zhang, Yuanyuan Pan, Gang Liu
Acremonium chrysogenum is the industrial producer of cephalosporin C (CPC). We isolated a mutant (AC554) from a T-DNA inserted mutant library of A. chrysogenum. AC554 exhibited a reduced conidiation and lack of CPC production. In consistent with it, the transcription of cephalosporin biosynthetic genes pcbC and cefEF was significantly decreased in AC554. Thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR) was performed and sequence analysis indicated that a T-DNA was inserted upstream of an open reading frame (ORF) which was designated AcmybA...
June 2, 2018: Fungal Genetics and Biology: FG & B
Kang Zhang, Xuemei Yuan, Jinping Zang, Min Wang, Fuxin Zhao, Peifen Li, Hongzhe Cao, Jianmin Han, Jihong Xing, Jingao Dong
A pathogenic mutant, BCG183, was obtained by screening the T-DNA insertion library of Botrytis cinerea . A novel pathogenicity-related gene BcKMO , which encodes kynurenine 3-monooxygenase (KMO), was isolated and identified via thermal asymmetric interlaced PCR, bioinformatics analyses, and KMO activity measurement. The mutant BCG183 grew slowly, did not produce conidia and sclerotia, had slender hyphae, and presented enhanced pathogenicity. The phenotype and pathogenicity of the BcKMO -complementing mutant (BCG183/ BcKMO ) were similar to those of the wild-type (WT) strain...
2018: Frontiers in Microbiology
Abhijit Sar, Srikanta Pal, Bomba Dam
Activity-based screening of metagenomic DNA libraries is a promising approach to fish out genes encoding novel bioactive compounds/enzymes of industrial importance. The starting point of such functional screening in fosmid vectors is isolation of high molecular weight (HMW) DNA of sufficient purity from diverse environments. Metagenomic DNA isolation protocols mostly employ mechanical cell lysis that yields fragmented DNA. Those established for HMW DNA using enzymatic lysis have not considered samples with high lignocellulose or humic acid content...
May 30, 2018: Applied Microbiology and Biotechnology
Alexander L Satz
Use of DNA-encoded libraries (DELs) in the pharmaceutical industry has rapidly increased. We discuss what to expect when you run a DEL screen and contemplate guidelines for library design. Additionally, we consider some visionary work and extrapolate to the future.
May 10, 2018: ACS Medicinal Chemistry Letters
Yi Wu, Rui-Ying Zhu, Leslie A Mitchell, Lu Ma, Rui Liu, Meng Zhao, Bin Jia, Hui Xu, Yun-Xiang Li, Zu-Ming Yang, Yuan Ma, Xia Li, Hong Liu, Duo Liu, Wen-Hai Xiao, Xiao Zhou, Bing-Zhi Li, Ying-Jin Yuan, Jef D Boeke
The power of synthetic biology has enabled the expression of heterologous pathways in cells, as well as genome-scale synthesis projects. The complexity of biological networks makes rational de novo design a grand challenge. Introducing features that confer genetic flexibility is a powerful strategy for downstream engineering. Here we develop an in vitro method of DNA library construction based on structural variation to accomplish this goal. The "in vitro SCRaMbLE system" uses Cre recombinase mixed in a test tube with purified DNA encoding multiple loxPsym sites...
May 22, 2018: Nature Communications
Robert Goodnow
No abstract text is available yet for this article.
June 2018: SLAS Discovery
Paul J J Hooykaas, G Paul H van Heusden, Xiaolei Niu, M Reza Roushan, Jalal Soltani, Xiaorong Zhang, Bert J van der Zaal
Two decades ago, it was discovered that the well-known plant vector Agrobacterium tumefaciens can also transform yeasts and fungi when these microorganisms are co-cultivated on a solid substrate in the presence of a phenolic inducer such as acetosyringone. It is important that the medium has a low pH (5-6) and that the temperature is kept at room temperature (20-25 °C) during co-cultivation. Nowadays, Agrobacterium-mediated transformation (AMT) is the method of choice for the transformation of many fungal species; as the method is simple, the transformation efficiencies are much higher than with other methods, and AMT leads to single-copy integration much more frequently than do other methods...
May 17, 2018: Current Topics in Microbiology and Immunology
Seungkirl Ahn, Biswaranjan Pani, Alem W Kahsai, Eva K Olsen, Gitte Husemoen, Mikkel Vestrgaard, Lei Jin, Shuai Zhao, Laura M Wingler, Paula K Rambarat, Rishabh K Simhal, Thomas T Xu, Lillian D Sun, Paul J Shim, Dean P Staus, Li-Yin Huang, Thomas Franch, Xin Chen, Robert J Lefkowitz
Conventional drug discovery efforts at the β2 -adrenoceptor (β2 AR) have led to the development of ligands that bind almost exclusively to the receptor's hormone-binding orthosteric site. However, targeting the largely unexplored and evolutionarily unique allosteric sites has potential for developing more specific drugs with fewer side effects than orthosteric ligands. Using our recently developed approach for screening G protein-coupled receptors (GPCRs) with DNA-encoded small molecule libraries, we have discovered and characterized the first β2 AR small molecule positive allosteric modulators (PAMs) - compound-6 [(R)-N-(4-amino-1-(4-(tert-butyl)phenyl)-4-oxobutan-2-yl)-5-(N-isopropyl-N-methylsulfamoyl)-2-((4-methoxyphenyl) thio)benzamide] and its analogs...
May 16, 2018: Molecular Pharmacology
Charles Nj Ravarani, Tamara Y Erkina, Greet De Baets, Daniel C Dudman, Alexandre M Erkine, M Madan Babu
Over 40% of proteins in any eukaryotic genome encode intrinsically disordered regions (IDRs) that do not adopt defined tertiary structures. Certain IDRs perform critical functions, but discovering them is non-trivial as the biological context determines their function. We present IDR-Screen, a framework to discover functional IDRs in a high-throughput manner by simultaneously assaying large numbers of DNA sequences that code for short disordered sequences. Functionality-conferring patterns in their protein sequence are inferred through statistical learning...
May 14, 2018: Molecular Systems Biology
Sabine Gogolok, Ute Köber, Steven M Pollard
Transcription activator-like effectors (TALEs) contain programmable DNA-binding domains that can be fused to various effectors to manipulate genetic sequences or transcriptional state. However, the construction of plasmids encoding the modular DNA-binding domain remains challenging due to their repetitive nature. Here, we describe methods for a simple TALE assembly reaction (STAR) that uses a 68-part plasmid library to create TALEs binding to 17 bp target sequences. Manual production of many tens of TALEs can be achieved using a simple 8 h protocol, with full length sequence-verified plasmids available within a few days...
2018: Methods in Molecular Biology
Joosu Kuivanen, Sami Holmström, Birgitta Lehtinen, Merja Penttilä, Jussi Jäntti
Due to the rapidly increasing sequence information on gene variants generated by evolution and our improved abilities to engineer novel biological activities, microbial cells can be evolved for the production of a growing spectrum of compounds. For high productivity, efficient carbon channeling towards the end product is a key element. In large scale production systems the genetic modifications that ensure optimal performance cannot be dependent on plasmid-based regulators, but need to be engineered stably into the host genome...
May 5, 2018: Biotechnology Journal
Nicholas Favalli, Gabriele Bassi, Jörg Scheuermann, Dario Neri
DNA-encoded chemical libraries (DECLs) are collections of compounds, individually coupled to DNA tags serving as amplifiable identification barcodes. Since individual compounds can be identified by the associated DNA tag, they can be stored as a mixture, allowing the synthesis and screening of combinatorial libraries of unprecedented size, facilitated by the implementation of split-and-pool synthetic procedures or other experimental methodologies. In this review, we briefly present relevant concepts and technologies, which are required for the implementation and interpretation of screening procedures with DNA-encoded chemical libraries...
April 23, 2018: FEBS Letters
Atilgan Yilmaz, Mordecai Peretz, Aviram Aharony, Ido Sagi, Nissim Benvenisty
The maintenance of pluripotency requires coordinated expression of a set of essential genes. Using our recently established haploid human pluripotent stem cells (hPSCs), we generated a genome-wide loss-of-function library targeting 18,166 protein-coding genes to define the essential genes in hPSCs. With this we could allude to an intrinsic bias of essentiality across cellular compartments, uncover two opposing roles for tumour suppressor genes and link autosomal-recessive disorders with growth-retardation phenotypes to early embryogenesis...
May 2018: Nature Cell Biology
Yun Ding, Jing Chai, Paolo A Centrella, Chenaimwoyo Gondo, Jennifer L DeLorey, Matthew A Clark
Encoded library technology (ELT) is an effective approach to the discovery of novel small-molecule ligands for biological targets. A key factor for the success of the technology is the chemical diversity of the libraries. Here we report the development of DNA-conjugated benzimidazoles. Using 4-fluoro-3-nitrobenzoic acid as a key synthon, we synthesized a 320 million-member DNA-encoded benzimidazole library using Fmoc-protected amino acids, amines and aldehydes as diversity elements. Affinity selection of the library led to the discovery of a novel, potent and specific antagonist of the NK3 receptor...
May 14, 2018: ACS Combinatorial Science
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