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Proteins as Biocatalysts for Atom Transfer Radical Polymerization (ATRPase)

English title Proteins as Biocatalysts for Atom Transfer Radical Polymerization (ATRPase)
Applicant Bruns Nico
Number 140693
Funding scheme Project funding
Research institution Physikalische Chemie Departement Chemie Universität Basel
Institution of higher education University of Basel - BS
Main discipline Physical Chemistry
Start/End 01.04.2012 - 30.09.2013
Approved amount 140'000.00
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Keywords (7)

Protein; Enzyme; Biocatalysis; Polymer; Atom Transfer Radical Polymerization; ATRP; Controlled radical polymerization

Lay Summary (English)

Lead
Lay summary

Polymerization reactions that allow synthesizing polymers with predetermined molecular weights, with narrow molecular weight distributions and with functional end groups have propelled polymer science into the position of key contributor to advanced materials, nanosciences, and modern soft matter research. Such “living” or controlled polymerizations are used e.g. to synthesize amphiphilic blockcopolymers, which are needed as building blocks of self-assembled nanoobjects. Atom transfer radical polymerization (ATRP) is one of the most widely used controlled radical polymerizations. However, ATRP requires the use of transition metal complexes as catalysts. They are difficult to remove from the polymer product and are often toxic as well as environmentally unfavorable. Recently, we discovery that some heme proteins and enzymes can catalyze the polymerization of an acrylamide under conditions of activators regenerated by electron transfer (ARGET) ATRP. The previously unknown enzymatic catalysis was termed ATRPase activity. As enzymes and proteins are non-toxic and environmental friendly, ATRPases could become “green” alternatives to transition metal catalysts used in ATRP.

Based on these initial findings, the proposed project will investigate the ATRPase activity of hemoglobin and of horseradish peroxidase in detail, in order to understand the mechanism of the reaction and the role of the biocatalyst, to quantify the rate constants of the reactions involved in ATRP, to identify and suppress possible side reactions, and to increase the degree of control over the polymerization. We expect that also other metalloenzymes and –proteins will show catalytic activity in ATRP reactions. Therefore, a diverse library of proteins and enzymes will be screened for this activity. Moreover, the potential of ATRPase activity will be investigated by using various monomers, synthesizing block copolymers and star-shaped polymers, and by investigating the operational stability and reusability of soluble and immobilized biocatalysts.

In summary, the major aims of this project are to gain detailed knowledge of the molecular processes involved in ATRPase activity, to elucidate the scope of biocatalytic ATRP and to improve the catalytic performance of ATRPases to such levels that they become competitive, environmentally favorable alternatives to conventional ATRP catalysts.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
A Chaperonin as Protein Nanoreactor for Atom-Transfer Radical Polymerization
Renggli Kasper, Nussbaumer Martin G., Urbani Raphael, Pfohl Thomas, Bruns Nico (2014), A Chaperonin as Protein Nanoreactor for Atom-Transfer Radical Polymerization, in Angew. Chem., Int. Ed., 53(5), 1443-1447.
Biocatalytic ATRP: Controlled Radical Polymerizations Mediated by Enzymes
Renggli Kasper, Spulber Mariana, Pollard Jonas, Bruns Nico (2013), Biocatalytic ATRP: Controlled Radical Polymerizations Mediated by Enzymes, in Smith Patrick B., Gross Richard A., Cheng H. N. (ed.), American Chemical Society, Washington, DC, 163-171.
Combining Polymers with the Functionality of Proteins: New Concepts for Atom Transfer Radical Polymerization, Nanoreactors and Damage Self-reporting Materials
Bruns Nico, Lörcher Samuel, Makyła Katarzyna, Pollard Jonas, Renggli Kasper, Spulber Mariana (2013), Combining Polymers with the Functionality of Proteins: New Concepts for Atom Transfer Radical Polymerization, Nanoreactors and Damage Self-reporting Materials, in Chimia, 67(11), 777-781.
Hemoglobin and Red Blood Cells Catalyze Atom Transfer Radical Polymerization
Silva Tilana B., Spulber Mariana, Kocik Marzena K., Seidi Farzad, Charan Himanshu, Rother Martin, Sigg Severin J., Renggli Kasper, Kali Gergely, Bruns Nico (2013), Hemoglobin and Red Blood Cells Catalyze Atom Transfer Radical Polymerization, in Biomacromolecules, 14(8), 2703-2712.

Collaboration

Group / person Country
Types of collaboration
Dr. Cornelia Palivan Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
Prof. Wolfgang Meier Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Fall Meeting of the Swiss Chemical Society Poster Protein Nanoreactors and Native Enzymes for Controlled Radical Polymerization in Aqueous Solution 06.09.2013 Lausanne, Switzerland Renggli Kasper; Bruns Nico;
EPF 2013 - European Polymer Congress Talk given at a conference Biocatalytic ATRP: Controlled Radical Polymerizations Mediated by Enzymes 16.06.2013 Pisa, Italy Renggli Kasper; Bruns Nico; Pollard Jonas;
PolyColl 2013 Poster Enzyme-catalyzed ATRP. Investigation of kinetics and rate constants determination 07.06.2013 Basel, Switzerland Bruns Nico; Renggli Kasper;
PolyColl 2013 Poster Protein Nanoreactors and Native Enzymes for Controlled Radical Polymerization in Aqueous Solution 07.06.2013 Basel, Switzerland Bruns Nico; Renggli Kasper;
Swiss NanoConvention Poster Controlled Radical Polymerization in Protein Nanoreactors and with Native Enzymes 23.05.2013 Basel, Switzerland Bruns Nico; Renggli Kasper;
Frontiers in Polymer Science Poster Enzyme-catalyzed ATRP. Investigation of kinetics and rate constants determination 21.05.2013 Sitges, Barcelona, Spain Renggli Kasper; Bruns Nico;
Macro BeGe Poster Enzyme-catalyzed ATRP in polymersome nanoreactors 03.12.2012 Houffalize, Belgium Renggli Kasper; Bruns Nico;
11th Greta Pifat Mrzljak International School of Biophysics 2012 Talk given at a conference Controlled Radical Polymerization in Protein Nanoreactors and with Native Enzymes 02.10.2012 Primošten, Croatia Bruns Nico; Renggli Kasper;
11th Greta Pifat Mrzljak International School of Biophysics Poster Controlled Radical Polymerization in Protein Nanoreactors and with Native Enzymes 02.10.2012 Primošten, Croatia Renggli Kasper; Bruns Nico;
Symposium on "Green Polymer Chemistry: Biocatalysis and Biobased Materials", 244th ACS National Meeting Talk given at a conference ATRPases: Enzymes as catalysts for atom transfer radical polymerization 19.08.2012 Philadeliphia, PA, United States of America Bruns Nico; Renggli Kasper;
Warwick Polymer Conference Talk given at a conference ATRPases: Enzymes that catalyze Atom Transfer Radical Polymerization 09.07.2012 Warwick, Great Britain and Northern Ireland Bruns Nico;
Fachhochschule Nordwestschweiz Summer School in Macromolecular Chemistry Individual talk Polymer-Protein Hybrid Materials 25.06.2012 Muttenz, Switzerland Bruns Nico;
Swiss Soft Days 8 Talk given at a conference Controlled Polymerization in Protein Nanoreactors and with Native Enzymes 01.06.2012 Geneva, Switzerland Renggli Kasper; Bruns Nico;


Self-organised

Title Date Place
PolyColl 2013 07.06.2013 Basel, Switzerland

Associated projects

Number Title Start Funding scheme
144697 Controlled Radical Polymerization Catalyzed by Enzymes: From Fundamentals to Applications 01.10.2013 SNSF Professorships

Abstract

Polymerization reactions that allow the synthesis of polymers with predetermined molecular weights, with narrow molecular weight distributions and with functional end groups have propelled polymer science into the position of key contributor to advanced materials, nanosciences, and modern soft matter research. Such “living” or controlled polymerizations are used e.g. to synthesize amphiphilic blockcopolymers, which are needed as building blocks of self-assembled nanoobjects. Atom transfer radical polymerization (ATRP) is one of the most widely used controlled radical polymerizations. However, ATRP requires the use of transition metal complexes as catalysts, and these are difficult to remove from the polymer products and are often toxic as well as environmentally unfavorable. Recently, we discovery that the heme protein hemoglobin (Hb) and the heme enzyme horseradish peroxidase (HRP) can catalyze the polymerization of an acrylamide under conditions of activators regenerated by electron transfer (ARGET) ATRP. The previously unknown enzymatic catalysis was termed ATRPase activity. As enzymes and proteins are non-toxic and environmental friendly, ATRPases could become green alternatives to transition metal complex catalysts used in ATRP.Based on these initial findings, the proposed project will investigate the ATRPase activity of Hb and HRP in detail, in order to understand the mechanism of the reaction and the role of the biocatalyst, to quantify the rate constants of the reactions involved in ATRP, to identify and suppress possible side reactions, and to increase the degree of control over the polymerization. Moreover, the potential of ATRPase activity in water will be investigated by using various monomers, synthesizing block copolymers and star-shaped polymers, and by investigating the operational stability and reusability of soluble and immobilized biocatalysts.We expect that not only Hb and HRP, but also other metalloenzymes and -proteins will show catalytic activity in ATRP reactions. Therefore, a diverse library of proteins and enzymes will be screened with an assay for ATRPase activity in a microtiter plate format. The biomolecules will include heme-proteins such as myoglobin, heme-enzymes such as cytochromes, Cu-containing enzymes and proteins such as tyrosinase, as well as Mn-and Ni-containing enzymes. Positive hits resulting from this screening will be further characterized with respect to their polymerization activity and reaction conditions will be optimized for good catalytic performance. These studies will allow a determination of which structural and redox properties of proteins and enzymes are essential for ATRPase activity to occur. ATRPase activity has so far been observed in polymerization reactions that were carried out in water. However, a range of monomers and polymers are hydrophobic and therefore not soluble in water. Thus, it would significantly broaden the scope of enzyme/protein-catalyzed ATRP if these reactions could be conducted in non-aqueous media. Given the fact that enzymes are known to be stable and active under suitable conditions in these media, several approaches will be followed to render ATRPases compatible with organic solvents. Lyophilized enzyme/protein powders and immobilized biocatalysts will be suspended in organic solvents. Also, the biocatalysts will be solubilized in organic solvents by the formation of ion pairs with surfactants, and by covalent conjugation to polymers. Suitable reaction conditions for ARGET ATRP in solvents of different polarities ranging from hexane to ethanol will be identified and the catalytic performance of the ATRPase preparations will be characterized. Moreover, mechanistic aspects of ATRPase activity in non-aqueous media will be studied. In summary, the major aims of this project are to gain detailed knowledge of the molecular processes involved in ATRPase activity, to elucidate the scope of biocatalytic ATRP and to improve the catalytic performance of ATRPases to such levels that they become competitive, environmentally favorable alternatives to conventional ATRP catalysts.
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