Read by QxMD icon Read


Theo Peschke, Kersten S Rabe, Christof M Niemeyer
We herein describe the engineering of E. coli strains that display orthogonal tags for immobilization on their surface and overexpress a functional heterologous "protein content" in their cytosol at the same time. Using the outer membrane protein Lpp-ompA, cell-surface display of the streptavidin-binding peptide, the SpyTag/SpyCatcher system, or a HaloTag variant allowed us to generate bacterial strains that can selectively bind to solid substrates, as demonstrated with magnetic microbeads. The simultaneous cytosolic expression of functional content was demonstrated for fluorescent proteins or stereoselective ketoreductase enzymes...
January 20, 2017: Angewandte Chemie
Kelly Dumorné, David Camacho Córdova, Marcia Astorga-Eló, Prabhaharan Renganathan
Extremophilic microorganisms have established a diversity of molecular strategies in order to survive in extreme conditions. Biocatalysts isolated by these organisms are termed extremozymes, possess extraordinary properties are salt allowance thermostability and cold adaptivity. Extremozymes are very resistant in extreme conditions due to their great solidity and they propose new opportunities for biocatalysis and biotransformations, also for the development of the economy and new line of research through their application...
January 20, 2017: Journal of Microbiology and Biotechnology
Yingbiao Zhou, Yueming Zhu, Yan Men, Caixia Dong, Yuanxia Sun, Juankun Zhang
There are excessive by-products in the biocatalysis process of this whole-cell biocatalytic production of melibiose from raffinose with current Saccharomyces cerevisiae strains. To solve this problem, we constructed engineered strains based on a liquor yeast (S. cerevisiae) via gene deletion (mel1 gene), heterologous integration (fsy1 or/and ffzi1 gene from Candida magnoliae), and gene overexpression (gcr1 gene). Functional verification showed that deletion of the mel1 gene led to elimination of the reactions catalyzed by α-galactosidase, as well as elimination of the degradation of melibiose and the formation of galactose by-product...
January 18, 2017: Journal of Industrial Microbiology & Biotechnology
Anisha N Patel, Agnès Anne, Arnaud Chovin, Christophe Demaille, Eric Grelet, Thierry Michon, Cécilia Taofifenua
Organizing active enzyme molecules on nanometer-sized scaffolds is a promising strategy for designing highly efficient supported catalytic systems for biosynthetic and sensing applications. This is achieved by designing model nanoscale enzymatic platforms followed by thorough analysis of the catalytic activity. Herein, the virus fd bacteriophage is considered as an enzyme nanocarrier to study the scaffolding effects on enzymatic activity. Nanoarrays of randomly oriented, or directionally patterned, fd bacteriophage virus are functionalized with the enzyme glucose oxidase (GOx), using an immunological assembly strategy, directly on a gold electrode support...
January 18, 2017: Small
Jan M Klenk, Bernd A Nebel, Joanne L Porter, Justyna K Kulig, Shaneela A Hussain, Sven M Richter, Michele Tavanti, Nicholas J Turner, Martin A Hayes, Bernhard Hauer, Sabine L Flitsch
P450 monooxygenases are able to catalyse the highly regio- and stereoselective oxidations of many organic molecules. However, the scale-up of such bio-oxidations remains challenging due to the often-low activity, level of expression and stability of P450 biocatalysts. Despite these challenges they are increasingly desirable as recombinant biocatalysts, particularly for the production of drug metabolites. Diclofenac is a widely used anti-inflammatory drug that is persistent in the environment along with the 4'- and 5-hydroxy metabolites...
January 18, 2017: Biotechnology Journal
Bettina M Nestl, Christopher Geinitz, Stephanie Popa, Sari Rizek, Robert J Haselbeck, Rosary Stephen, Michael A Noble, Max-Philipp Fischer, Erik C Ralph, Hoi Ting Hau, Henry Man, Muhiadin Omar, Johan P Turkenburg, Stephen van Dien, Stephanie J Culler, Gideon Grogan, Bernhard Hauer
The asymmetric dehydration of alcohols is an important process for the direct synthesis of alkenes. We report the structure and substrate specificity of the bifunctional linalool dehydratase isomerase (LinD) from the bacterium Castellaniella defragrans that catalyzes in nature the hydration of β-myrcene to linalool and the subsequent isomerization to geraniol. Enzymatic kinetic resolutions of truncated and elongated aromatic and aliphatic tertiary alcohols (C5-C15) that contain a specific signature motif demonstrate the broad substrate specificity of LinD...
January 9, 2017: Nature Chemical Biology
Yuchen Zhou, Junjie Huang, Wei Sun, Yuanlai Ju, Pinghui Yang, Lingyun Ding, Zhongren Chen, Julia A Kornfield
Patterned porous surfaces with responsive functionalities are fabricated by a thermo-responsive microgel-assisted breath figure (BF) process. When water droplets submerge into a polystyrene (PS) solution during formation of a porous surface by the bottom-up BF process, poly(N-isopropylacrylamide)-co-acrylic acid (PNIPAm-co-AA) microgels dispersed in the solution spontaneously assemble at the water-organic interfaces like "Pickering emulsions", reinforced by capillary flow. The conformal layer of PNIPAm-co-AA microgels lining the pores appears in images of scanning electron microscope (SEM) either as a smooth surface layer (L) or as an array of dome-like protrusions (D), depending on the conditions at which the sample was dried for SEM...
January 9, 2017: ACS Applied Materials & Interfaces
Holly A Reeve, Philip A Ash, HyunSeo Park, Ailun Huang, Michalis Posidias, Chloe Tomlinson, Oliver Lenz, Kylie A Vincent
The present study considers the ways in which redox enzyme modules are coupled in living cells for linking reductive and oxidative half-reactions, and then reviews examples in which this concept can be exploited technologically in applications of coupled enzyme pairs. We discuss many examples in which enzymes are interfaced with electronically conductive particles to build up heterogeneous catalytic systems in an approach which could be termed synthetic biochemistry We focus on reactions involving the H(+)/H2 redox couple catalysed by NiFe hydrogenase moieties in conjunction with other biocatalysed reactions to assemble systems directed towards synthesis of specialised chemicals, chemical building blocks or bio-derived fuel molecules...
January 15, 2017: Biochemical Journal
Nora Weber, Marie Gorwa-Grauslund, Magnus Carlquist
BACKGROUND: Whole-cell biocatalysis based on metabolically active baker's yeast with engineered transamination activity can be used to generate molecules carrying a chiral amine moiety. A prerequisite is though to express efficient ω-transaminases and to reach sufficient intracellular precursor levels. RESULTS: Herein, the efficiency of three different ω-transaminases originating from Capsicum chinense, Chromobacterium violaceum, and Ochrobactrum anthropi was compared for whole-cell catalyzed kinetic resolution of racemic 1-phenylethylamine to (R)-1-phenylethylamine...
January 3, 2017: Microbial Cell Factories
Guangda Han, Jin-Tao Wang, Xiaotian Ji, Li Liu, Hanying Zhao
Proteinosomes are a type of protein-based spherical capsules, which have potential applications in drug delivery, cell imaging, gene expression and biocatalysis. In this research, a novel approach to the fabrication of proteinosomes entirely composed of protein molecules based on self-assembly of a supramolecular protein-polymer conjugate, is proposed. A supramolecular protein-polymer conjugate was prepared by mixing βCD-modified bovine serum albumin (BSA) and adamantane-terminated poly(N-isopropylamide) (Ad-PNIPAM) in aqueous solution...
December 30, 2016: Bioconjugate Chemistry
Christian Gehring, Mirja Wessel, Steffen Schaffer, Oliver Thum
Microbially derived surfactants, so-called biosurfactants, have drawn much attention in recent years and are expected to replace current petrochemical surfactants, owing to their environmental and toxicological benefits. One strategy to support that goal is to reduce production costs by replacing relatively expensive sugars with cheaper raw materials, such as short-chain alkanes. Herein, we report the successful one-pot total synthesis of rhamnolipids, a class of biosurfactants with 12 stereocenters, from butane as sole carbon and energy source through the design of a tailored whole-cell biocatalyst...
December 2016: ChemistryOpen
Maximilian J L J Fürst, Simone Savino, Hanna M Dudek, J Rúben Gómez Castellanos, Cora Gutiérrez de Souza, Stefano Rovida, Marco W Fraaije, Andrea Mattevi
Regio- and stereoselective Baeyer-Villiger oxidations are difficult to achieve by classical chemical means, particularly when large, functionalized molecules are to be converted. Biocatalysis using flavin-containing Baeyer-Villiger monooxygenases (BVMOs) is a well-established tool to address these challenges, but known BVMOs have shortcomings in either stability or substrate selectivity. We characterized a novel BVMO from the thermophilic fungus Thermothelomyces thermophila, determined its three-dimensional structure, and demonstrated its use as a promising biocatalyst...
January 18, 2017: Journal of the American Chemical Society
Guangtong Chen, Jie Li, Sensen Yan, Haijun Lin, Juanjuan Wu, Xuguang Zhai, Yan Song, Jianlin Li
Biocatalysis of 20(R)-panaxatriol (PT) was performed by the fungus Mucor racemosus. Six metabolites (1-6) including five new compounds were obtained, and their structures were elucidated as 20(R),25-epoxy-12β,24β-dihydroxydammaran-3,6-dione (2), 20(R),25-epoxy-12β,22β-dihydroxydammaran-3,6-dione (3), 20(R),25-epoxy-23β-hydroxydammaran-3,6,12-trione (4), 20(R),25-epoxy-12β,23α- dihydroxydammaran-3,6-dione (5), and 20(R),25-epoxy-12β-hydroxydammaran-3,6,23-trione (6) by spectroscopic analysis. Pharmacological studies revealed that compounds 2, 3 and 5 exhibited significant antihepatic fibrosis activity, while 4 and 6 showed cytotoxicity against HSC-T6 cells...
December 22, 2016: Natural Product Research
Tao Xie, Chao Jing, Yi-Tao Long
Plasmonic nanoparticles, especially Au and Ag, exhibit unique and tuneable optical properties due to their localized surface plasmon resonance, which have been widely applied in cell imaging, biocatalysis and biosensing. Notably, dark-field microscopy enables the observation of the scattering spectra of single nanoparticles and therefore has been intensively used in the construction of various nanosensors. In this mini review, we will briefly introduce the recent applications of plasmonic nanoparticles based on dark-field microscopy...
December 22, 2016: Analyst
Susana Velasco-Lozano, Ana I Benítez-Mateos, Fernando López-Gallego
Enzyme cofactors play a major role in biocatalysis, as many enzymes require them to catalyze highly valuable reactions in organic synthesis. However, the cofactor recycling is often a hurdle to implement enzymes at the industrial level. The fabrication of heterogeneous biocatalysts co-immobilizing phosphorylated cofactors (PLP, FAD(+) , and NAD(+) ) and enzymes onto the same solid material is reported to perform chemical reactions without exogeneous addition of cofactors in aqueous media. In these self-sufficient heterogeneous biocatalysts, the immobilized enzymes are catalytically active and the immobilized cofactors catalytically available and retained into the solid phase for several reaction cycles...
December 21, 2016: Angewandte Chemie
Caitlin Deane
No abstract text is available yet for this article.
December 16, 2016: Nature Chemical Biology
Long Chen, Ashok Mulchandani, Xin Ge
Taking the advantages of inert and stable nature of endospores, we developed a biocatalysis platform for multiple enzyme immobilization on Bacillus subtilis spore surface. Among B. subtilis outer coat proteins, CotG mediated a high expression level of Clostridium thermocellum cohesin (CtCoh) with a functional display capability of ∼10(4) molecules per spore of xylose reductase C. termocellum dockerin fusion protein (XR-CtDoc). By co-immobilization of phosphite dehydrogenase (PTDH) on spore surface via Ruminococcus flavefaciens cohesin-dockerin modules, regeneration of NADPH was achieved...
December 15, 2016: Biotechnology Progress
Jasper O Ojoghoro, Abdul J Chaudhary, Pablo Campo, John P Sumpter, Mark D Scrimshaw
Progesterone is a natural hormone, excreted in higher concentrations than estrogens, and has been detected in the aqueous environment. As with other compounds, it is transformed during wastewater treatment processes and in the environment. However, minor modifications to the structure may result in transformation products which still exhibit biological activity, so understanding what transformation products are formed is of importance. The current study was undertaken to identify putative transformation products resulting from spiking river water with progesterone in a laboratory-based degradation study and hence to follow the metabolic breakdown pathways...
February 1, 2017: Science of the Total Environment
Rashida Akter, Damien W M Arrigan
A label-free electrochemical strategy for the detection of a cancer biomarker, prostate specific membrane antigen (PSMA), at picomolar concentrations without the use of antibodies, was investigated. The approach is based on the assisted ion transfer of protons, generated by a series of enzymatic reactions, at an array of microinterfaces between two immiscible electrolyte solutions (μ-ITIES). This nonredox electrochemical approach based on biocatalysis-coupled proton transfer at the μ-ITIES array opens a new way to detect the prostate cancer biomarker, with detection capability achieved at concentrations below those indicative of disease presence...
December 6, 2016: Analytical Chemistry
Qi Sun, Briana Aguila, Jason Perman, Nicholas Nguyen, Shengqian Ma
The combination of two or more reactive centers working in concert on a substrate to facilitate the reaction is now considered state of the art in catalysis, yet there still remains a tremendous challenge. Few heterogeneous systems of this sort have been exploited, as the active sites spatially separated within the rigid framework are usually difficult to cooperate. It is now shown that this roadblock can be surpassed. The underlying principle of the strategy presented here is the integration of catalytic components with excellent flexibility and porous heterogeneous catalysts, as demonstrated by the placement of linear ionic polymers in close proximity to surface Lewis acid active sites anchored on the walls of a covalent organic framework (COF)...
December 7, 2016: Journal of the American Chemical Society
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"