Exploring the 5-Substituted 2-Aminobenzothiazole-Based DNA Gyrase B Inhibitors Active against ESKAPE Pathogens

We present a new series of 2-aminobenzothiazole-basedDNA gyraseB inhibitors with promising activity against ESKAPE bacterial pathogens.Based on the binding information extracted from the cocrystal structureof DNA gyrase B inhibitor A, in complex with Escherichia coli GyrB24, we expanded the chemicalspace of the benzothiazole-based series to the C5 position of thebenzothiazole ring. In particular, compound E showedlow nanomolar inhibition of DNA gyrase (IC50 < 10 nM)and broad-spectrum antibacterial activity against pathogens belongingto the ESKAPE group, with the minimum inhibitory concentration <0.03 & mu;g/mL for most Gram-positive strains and 4-16 & mu;g/mLagainst Gram-negative E. coli, Acinetobacter baumannii, Pseudomonasaeruginosa, and Klebsiella pneumoniae. To understand the binding mode of the synthesized inhibitors, acombination of docking calculations, molecular dynamics (MD) simulations,and MD-derived structure-based pharmacophore modeling was performed.The computational analysis has revealed that the substitution at positionC5 can be used to modify the physicochemical properties and antibacterialspectrum and enhance the inhibitory potency of the compounds. Additionally,a discussion of challenges associated with the synthesis of 5-substituted2-aminobenzothiazoles is presented

Improved bacterial recombineering by parallelized protein discovery

Exploiting bacteriophage-derived homologous recombination processes has enabled precise, multiplex editing of microbial genomes and the construction of billions of customized genetic variants in a single day. The techniques that enable this, multiplex automated genome engineering (MAGE) and directed evolution with random genomic mutations (DIvERGE), are however, currently limited to a handful of microorganisms for which single-stranded DNA-annealing proteins (SSAPs) that promote efficient recombineering have been identified. Thus, to enable genome-scale engineering in new hosts, efficient SSAPs must first be found. Here we introduce a highthroughput method for SSAP discovery that we call "serial enrichment for efficient recombineering" (SEER). By performing SEER in Escherichia coli to screen hundreds of putative SSAPs, we identify highly active variants PapRecT and CspRecT. CspRecT increases the efficiency of single-locus editing to as high as 50% and improves multiplex editing by 5- to 10-fold in E. coli, while PapRecT enables efficient recombineering in Pseudomonas aeruginosa, a concerning human pathogen. CspRecT and PapRecT are also active in other, clinically and biotechnologically relevant enterobacteria. We envision that the deployment of SEER in new species will pave the way toward pooled interrogation of genotype-to-phenotype relationships in previously intractable bacteria