Controlling the Selectivity and Stability of Proteins by New Strategies in Directed Evolution: The Case of Organocatalytic Enzymes

This chapter examines the politics of the currency in West Africa from the beginning of the twentieth century. A public series of debates over the nature of the currency occurred in West Africa during both the colonial and independence periods. Since 1983, West African countries have been pioneers in Africa in developing new strategies to combat overvaluation of the currency and reduce the control of government over the currency supply. The chapter charts the evolution of West African currencies as boundaries and explores their relationship to state consolidation. It shows that leaders in African capitals managed to make the units they ruled increasingly distinct from the international and regional economies, but the greater salience of the currency did not end up promoting state consolidation. Rather, winning the ability to determine the value of the currency led to a series of disastrous decisions that severely weakened the states themselves.

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Internationalization in Higher Education in Russia: Challenges, Lessons and Prospects of Collaboration with Vietnam

VNU Journal of Science Policy and Management Studies ◽

10.25073/2588-1116/vnupam.4099 ◽

2017 ◽

Vol 33 (2) ◽

Author(s):

Natalia Kraevskaia

Keyword(s):

Higher Education ◽

Education Reform ◽

Knowledge Production ◽

Professional Training ◽

National Interests ◽

International Networks ◽

International Dimension ◽

Main Factors ◽

Internationalization In Higher Education ◽

New Strategies

The article addresses the needs of educational system in context of rapidly developing globalization and explores internationalization of higher education as one of the main factors which contributes to integration of international dimension to professional training at universities. Different components and strategies of internationalization, such as strong collaboration in teaching, internationalization of the curriculum, cooperation in researches and knowledge production, students and professors’ mobility, and participation in international networks are analyzed in connection to education reform in Russia. The article provides the comparison of internationalization policies in Russian and Vietnamese education systems, argues that innovations in higher education should be adjusted to the national interests, traditions and mentality and finally describes new strategies in collaboration of Russia and Vietnam in the field of education.

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The intermolecular anthracene-transfer in a regiospecific antipodal C60 difunctionalization

10.26434/chemrxiv.11968743.v2 ◽

2020 ◽

Author(s):

Radu Talmazan ◽

Klaus R. Liedl ◽

Bernhard Kräutler ◽

Maren Podewitz

Keyword(s):

Noncovalent Interactions ◽

Interaction Model ◽

Alder Reaction ◽

Diels Alder ◽

Stacking Interactions ◽

Pi Stacking ◽

Diels Alder Reaction ◽

Double Decker ◽

Anthracene Molecule ◽

New Strategies

We analyze the mechanism of the topochemically controlled difunctionalization of C60 and anthracene, where an anthracene molecule is transferred from one C60 monoadduct to another one under exclusive formation of equal amounts of C60 and the difficult to make antipodal C60 bisadduct. Our herein disclosed dispersion corrected DFT studies show the anthracene transfer to take place in a synchronous retro Diels-Alder/Diels-Alder reaction: an anthracene molecule dissociates from one fullerene under formation of an intermediate, while already undergoing stabilizing interactions with both neighboring fullerenes, facilitating the reaction kinetically. In the intermediate, a planar anthracene molecule is sandwiched between two neighboring fullerenes and forms equally strong "double-decker" type pi-pi stacking interactions with both of these fullerenes. Analysis with the distorsion interaction model shows that the anthracene unit of the intermediate is almost planar with minimal distorsions. This analysis sheds light on the existence of noncovalent interactions engaging both faces of a planar polyunsaturated ring and two convex fullerene surfaces in an unprecedented 'inverted sandwich' structure. Hence, it sheds light on new strategies to design functional fullerene based materials.

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Directed Evolution of P450 Fatty Acid Decarboxylases via High-Throughput Screening Towards Improved Catalytic Activity

10.26434/chemrxiv.9791162 ◽

2019 ◽

Author(s):

Huifang Xu ◽

Weinan Liang ◽

Linlin Ning ◽

Yuanyuan Jiang ◽

Wenxia Yang ◽

...

Keyword(s):

Catalytic Activity ◽

Fatty Acid ◽

Directed Evolution ◽

High Throughput ◽

High Throughput Screening ◽

Colorimetric Detection ◽

Screening Method ◽

Random Mutagenesis ◽

Direct Production ◽

Consumption Activity

P450 fatty acid decarboxylases (FADCs) have recently been attracting considerable attention owing to their one-step direct production of industrially important 1-alkenes from biologically abundant feedstock free fatty acids under mild conditions. However, attempts to improve the catalytic activity of FADCs have met with little success. Protein engineering has been limited to selected residues and small mutant libraries due to lack of an effective high-throughput screening (HTS) method. Here, we devise a catalase-deficient Escherichia coli host strain and report an HTS approach based on colorimetric detection of H2O2-consumption activity of FADCs. Directed evolution enabled by this method has led to effective identification for the first time of improved FADC variants for medium-chain 1-alkene production from both DNA shuffling and random mutagenesis libraries. Advantageously, this screening method can be extended to other enzymes that stoichiometrically utilize H2O2 as co-substrate.

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