Category Archives: SCIENCE

Adaptive laboratory evolution reveals general and specific chemical tolerance mechanisms and enhances biochemical production

Rebecca M. Lennen, Kristian Jensen, Elsayed T. Mohammed, Sailesh Malla, Rosa A. Börner, Ksenia Chekina, Emre Özdemir, Ida Bonde, Anna Koza, Jérôme Maury, Lasse E. Pedersen, Lars Y. Schöning, Nikolaus Sonnenschein, Bernhard O. Palsson, Morten O.A. Sommer, Adam M. Feist, Alex T. Nielsen, Markus J. Herrgård

Tolerance to high product concentrations is a major barrier to achieving economically viable processes for bio-based chemical production. Chemical tolerance mechanisms are often unknown, thus their rational design is not achievable. To reveal unknown tolerance mechanisms we used an automated platform to evolve Escherichia coli to grow in previously toxic concentrations of 11 chemicals that have applications as polymer precursors, chemical intermediates, or biofuels. Read more

Engineering Corynebacterium glutamicum to produce the biogasoline isopentenol from plant biomass hydrolysates

Yusuke Sasaki, Thomas Eng, Robin A. Herbert, Jessica Trinh, Yan Chen, Alberto Rodriguez, John Gladden, Blake A. Simmons, Christopher J. Petzold and Aindrila Mukhopadhyay

Background: Many microbes used for the rapid discovery and development of metabolic pathways have sensitivities to final products and process reagents. Isopentenol (3-methyl-3-buten-1-ol), a biogasoline candidate, has an established heterologous gene pathway but is toxic to several microbial hosts. Reagents used in the pretreatment of plant biomass, such as ionic liquids, also inhibit growth of many host strains. We explored the use of Corynebacterium glutamicum as an alternative host to address these constraints. Read more

Detection and Characterization of a Mycobacterial L-Arabinofuranose ABC Transporter Identified with a Rapid Lipoproteomics Protocol

Miaomiao Li, Christoph Müller, Klemens Fröhlich, Oliver Gorka, Lin Zhang, Olaf Groß, Oliver Schilling, Oliver Einsle, Claudia Jessen-Trefzer

Nutrient uptake is essential for survival of organisms, and carbohydrates serve as a crucial carbon and energy source for most microorganisms. Given the importance of mycobacteria as human pathogens a detailed knowledge of carbohydrate uptake transporters is highly desirable, but currently available information is severely limited and mainly based on in silico analyses. Read more

Construction of Bacterial Cells with an Active Transport System for Unnatural Amino Acids

Wooseok Ko, Rahul Kumar, Sanggil Kim, and Hyun Soo Lee

Engineered organisms with an expanded genetic code have attracted much attention in chemical and synthetic biology research. In this work, engineered bacterial organisms with enhanced unnatural amino acid (UAA) uptake abilities were developed by screening periplasmic binding protein (PBP) mutants for recognition of UAAs. Read more

A TonB-dependent transporter is required for secretion of protease PopC across the bacterial outer membrane

Nuria Gómez-Santos, Timo Glatter, Ralf Koebnik, Magdalena Anna Świątek-Połatyńska & Lotte Søgaard-Andersen

TonB-dependent transporters (TBDTs) are ubiquitous outer membrane β-barrel proteins that import nutrients and bacteriocins across the outer membrane in a proton motive force-dependent manner, by directly connecting to the ExbB/ExbD/TonB system in the inner membrane. Read more

Analysis of SMALP co-extracted phospholipids shows distinct membrane environments for three classes of bacterial membrane protein

Alvin C. K. Teo, Sarah C. Lee, Naomi L. Pollock, Zoe Stroud, Stephen Hall, Alpesh Thakker, Andrew R. Pitt, Timothy R. Dafforn, Corinne M. Spickett & David I. Roper

Biological characterisation of membrane proteins lags behind that of soluble proteins. This reflects issues with the traditional use of detergents for extraction, as the surrounding lipids are generally lost, with adverse structural and functional consequences. Read more

Enhanced functionalisation of major facilitator superfamily transporters via fusion of C-terminal protein domains is both extensive and varied in bacteria

Benjamin J. Willson, Lindsey Dalzell, Liam N. M. Chapman, Gavin H. Thomas

The evolution of gene fusions that result in covalently linked protein domains is widespread in bacteria, where spatially coupling domain functionalities can have functional advantages in vivo.Fusions to integral membrane proteins are less widely studied but could provide routes to enhance membrane function in synthetic biology. Read more

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