Caulobacter crescentus is a bacterium with a distinctive life cycle and so it is studied as a cell development model. In addition, we have adapted this bacterium for recombinant protein production and display based on the crystalline surface protein (S)-layer and its C-terminal secretion signal. We report here the development of small, high-copy-number plasmid vectors and methods for producing an obligate expression host. The vectors are based on a narrow-host-range colE1-replicon-based plasmid commonly used in Escherichia coli, to which was added the replication origin of the IncQ plasmid RSF1010. C. crescentus strains were modified to enable plasmid replication by introduction of the RSF1010 repBAC genes at the recA locus. The small (4.0-4.5 kb) plasmids were in high copy numbers in both C. crescentus and E. coli and amenable to rapid methods for plasmid isolation and DNA sequencing. The method for introducing repBAC is suitable for other C. crescentus strains or any bacterium with an adequately homologous recA gene. Application of the vector for protein expression, based on the type I secretion system of the S-layer protein, when compared to constructs in broad-host-range plasmids, resulted in reduced time and steps required from clone construction to recombinant protein recovery and increased protein yield.
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http://dx.doi.org/10.1006/plas.2001.1530 | DOI Listing |
Acc Chem Res
January 2025
Shenzhen Grubbs Institute and Department of Chemistry, Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
ConspectusChiral organosilicon compounds bearing a Si-stereogenic center have attracted increasing attention in various scientific communities and appear to be a topic of high current relevance in modern organic chemistry, given their versatile utility as chiral building blocks, chiral reagents, chiral auxiliaries, and chiral catalysts. Historically, access to these non-natural Si-stereogenic silanes mainly relies on resolution, whereas their asymmetric synthetic methods dramatically lagged compared to their carbon counterparts. Over the past two decades, transition-metal-catalyzed desymmetrization of prochiral organosilanes has emerged as an effective tool for the synthesis of enantioenriched Si-stereogenic silanes.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Department of Physics, Indian Institute of Technology Delhi (IITD), Delhi 110016, India.
The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are considered to be the most important processes in metal-air batteries and regenerative fuel cell devices. Metal-organic polymers are attracting interest as promising precursors of advanced metal/carbon electrocatalysts because of their hierarchical porous structure along with the integrated metal-carbon framework. We developed carbon-coated CNTs with Ni/Fe and Cu/Fe as active sites.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
Hydration free energy (HFE) of molecules is a fundamental property having importance throughout chemistry and biology. Calculation of the HFE can be challenging and expensive with classical molecular dynamics simulation-based approaches. Machine learning (ML) models are increasingly being used to predict HFE.
View Article and Find Full Text PDFChem Rev
January 2025
Freie Universität Berlin, Institute of Chemistry and Biochemistry, 14195 Berlin, Germany.
Throughout history, we have looked to nature to discover and copy pharmaceutical solutions to prevent and heal diseases. Due to the advances in metabolic engineering and the production of pharmaceutical proteins in different host cells, we have moved from mimicking nature to the delicate engineering of cells and proteins. We can now produce novel drug molecules, which are fusions of small chemical drugs and proteins.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Electrical and Computer Engineering, The University of Tulsa, Tulsa, OK, United States of America.
As a non-contact method, the transient electromagnetic (TEM) method has the characteristics of high efficiency, small impact of device, no limitation of site range, and high resolution, and is a hot topic in current research. However, the research on the refined data processing method of TEM is lag, which seriously restricts the application in superficial engineering investigation and is a key problem that needs to be solved urgently. The particle swarm optimization (PSO) algorithm and firefly algorithm (FA) were successful swarm intelligence algorithms inspired by nature.
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