Why does Nature use modular enzyme architectures for biological catalysis?

Lead Research Organisation: University of Manchester
Department Name: Chemistry

Abstract

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Technical Summary

This proposal brings together a multi-disciplinary strength of Liverpool and Manchester to address a serious gap in our knowledge of some of the fundamental processes that underpin catalysis by redox enzymes involving proton-electron transfer. We will pursue an integrated programme drawing on the unique collaborative expertise formed by the applicants with expertise in biophysical, kinetic and enzymology studies (Manchester) and metalloenzyme crystallography, SFX and SEC-SAXS (Liverpool). Together we have published some significant papers on NiRs: JBC (2009), PNAS (2011), Biochemistry (2011) & Nature Comm (2014). Crucially, we provided recent evidence for long-range effects on enzyme mechanism resulting from mutations remote from the catalytic site, thus showing that efficient catalysis is controlled by basic design features of a number of elements that are inter-linked. Such knowledge is needed to design/redesign catalytic modules for synthetic biology in a predictable way.

We have invested significantly in obtaining important supporting data for this proposal. Key elements that make this proposal timely are (i) the development of new FRET-stopped flow approaches engineering to follow dynamics; (ii) discovery of 4-domain NiRs with additional cupredoxin and cytochrome domains fused to the core Cu1-Cu2 NiR, (iii) atomic structures of two members of cupredoxin-Cu1-Cu2NiR tethered complexes; (iv) supporting molecular biology/biochemical studies that enable expression and mutagenesis of most of the target proteins; (v) continued development of Liverpool's pioneering SEC-SAXS-DLS (size-exclusion chromatography-small angle X-ray scattering-dynamic light scattering) facility for use with proteins and their complexes. Our programme will provide deep understanding of how coordinated protein movements impact on (i) mechanisms of long-range ET, ii) localised chemical change (bond formation / breakage) and (iii) the utilization of coupled redox sites in a catalytic core.

Planned Impact

Beneficiaries. The beneficiaries of the research program are academic and industrial scientists within the international scientific community, as a strong knowledge base for predictive design of redox components will inform on future exploitation of these parts in synthetic biology and biotechnology. There is also a strong enabling methods theme in the program, which will benefit the wider dynamic structural science communities and time resolved spectroscopy community. We already engage strongly with instrument manufacturers, assisting them in the authoring of specialised application notes and adapting instruments for new capabilities by hosting industrial colleagues in our groups to assist in technology development. This should facilitate commercial developments from basic science research. We will continue to operate in this way with the explicit aim of enhancing laser spectroscopy and structural biology applications, and in developing wider appreciation of our novel laboratory-based methods (e.g. SEC-SAXS) being developed with both academic and commercial users.

Internationalisation. There is a strong international aspect to our program. We have teamed up with expert scientists at international facilities and we are working with technical scientists at Bruker Karlsruhe (Germany). This will enhance links with expert researchers in these areas, enabling exchange of research scientists (Bruker has established strong connections within the national EPR centre at Manchester). Extended visits by the PDRA/applicants to these groups will facilitate import of the knowledge back to the UK.
We will establish a series of workshops/symposia that will enable us to develop further links with international groups in the area of redox enzymes, structural biology, XFEL and predictive design for synthetic biology thereby facilitating better integration of their expertise in the UK research programs. These will take place at Liverpool and Manchester and we will also contribute to workshops at national/international facilities and BBSRC SBRC workshops.

Outreach. We will take advantage of the 'Discover days' hosted by the Faculty of Life Sciences at Manchester to introduce school children to the science underpinning biological catalysis. This is addition to our planned lectures at regional schools and other outreach activities (podcasts and participation in the annual MIB schools open day). Hasnain and Scrutton have, and continue to lecture to schoolchildren at science focus meetings on a variety of scientific topics. We will exhibit at both regional and national science exhibitions.

Communication. We will communicate and develop our infrastructure and approaches through frequent networking events with external stakeholders at structured workshops, showcase events and industry focussed meetings within the MIB (Manchester) and Life Sciences (Liverpool). In particular, we are developing new biophysical capabilities of broad interest to the academic and commercial communities. We will host a major symposium focused on the power of integrating biophysical and structural methods in the field of dynamic structural science. An important aspect here will be training and scientific development of younger workers. Our PDRAs will engage in science exhibitions and public lectures such as Science and Society Lectures at Liverpool and Manchester Science Festival, and we hope (with the applicants) at a Royal Society summer science exhibition.

Publications

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Lakavath B (2020) Radical-based photoinactivation of fatty acid photodecarboxylases. in Analytical biochemistry

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Rose SL (2022) Single crystal spectroscopy and multiple structures from one crystal (MSOX) define catalysis in copper nitrite reductases. in Proceedings of the National Academy of Sciences of the United States of America

 
Description Transient protein-protein complexes are ubiquitous in biology and are often involved in electron transfer processes essential to life (e.g. respiration and photosynthesis). Occasionally, proteins that are thought to interact through a transient complex are found in tethered in a single polypeptide chain. These fused proteins are often more efficient at catalysing biological electron transfer chemistry (e.g. P450 BM3) than their separated counterparts (e.g. P450 and P450 reductase). In this project, to understand and learn the role of redox partner tethering in nature, we have used protein 'reverse engineering' to isolated and study the 'core' and 'tethered' regions from the recently identified three-domain copper containing nitrite reductases (CuNiRs). Initial work was carried out on a CuNiR protein from Ralstonia picketti, a gram-negative bacterium. Ralstonia pickettii copper containing nitrite reductase (RpNiR) is thought to be a fusion of a cytochrome protein and the 'core' CuNiR protein. We studied the biophysical and structural properties of RpNiR and made comparisons to the well-characterised two-domain Alcaligenes xylosoxidans CuNiR (AxNiR) and its cytochrome partner protein (Ax cyt c). Our data show a range of unexpected roles of tethering in RpNiR catalysis. Specifically, we observed that tethering influences the affinity for substrate at the active site, the redox potentials of the enzyme, supresses reductive deactivation of the active site centre and promotes electron transfer processes (Hedison et al., ACS Catalysis, 2019).

A range of methods have been developed during this award, including the use of pH-jump spectroscopy to study proton coupled electron transfer (Hedison et al., Chem. Comm., 2019), cryo-reduction annealing (Hedison, et al., under revision) to study electron transfer processes and the use of protein 'reverse engineering' to study the structure of complex multicentre systems by pulsed electron-electron double resonance spectroscopy (Hedison et al., in preparation). These methodologies can be easily transferred for the study of other multicentre enzymes.
Exploitation Route Many of the approaches (pH-jump spectroscopy, cryo-reduction/annealing, and the use of protein 'reverse engineering' in combination with PELDOR spectroscopy) can be used to study electron transfer chemistry and protein structure. In future work, the outcomes presented from this award could be used to study both mechanism and structure of an array of redox enzymes. The knowledge gained from understanding the role of tethering in enzyme catalysis could help inform on the design of novel fusion enzymes for the biotech industry.
Sectors Agriculture, Food and Drink,Chemicals,Energy,Environment,Manufacturing, including Industrial Biotechology,Pharmaceuticals and Medical Biotechnology

 
Description The findings of this project have been embedded into early manufacturing pipelines in the EPSRC/BBSRC funded Future Biomanufacturing Research Hub (FBRH). In particular the use of modular enzyme systems for industrial biotechnology applications has been exploited and continues to be developed in a range of applications. The subsequent scale up of production is being explored with FBRH industry partners.
First Year Of Impact 2020
Sector Manufacturing, including Industrial Biotechology
Impact Types Economic

 
Description ACS Chemical Biology travel award for Tobias Hedison to attend 25th Enzyme Mechanisms Conference, Florida, USA
Amount $700 (USD)
Organisation American Chemical Society 
Sector Academic/University
Country United States
Start 01/2017 
End 01/2017
 
Title Cryo-reduction/annealing method 
Description Development of the cryo-reduction/annealing method to study electron transfer. 
Type Of Material Technology assay or reagent 
Year Produced 2019 
Provided To Others? No  
Impact n/a 
 
Title Protein 'reverse engineering' methods 
Description Development of protein 'reverse engineering' methods to study complex multicentre proteins by electron paramagnetic resonance measurements. 
Type Of Material Technology assay or reagent 
Year Produced 2019 
Provided To Others? No  
Impact n/a 
 
Title pH-jump method 
Description Development of pH-jump method to study the kinetics of proton coupled electron transfer. 
Type Of Material Technology assay or reagent 
Year Produced 2019 
Provided To Others? Yes  
Impact n/a 
 
Description MIB Open Day Stands/Tours 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact At Institute Open Day members of research group presented exhibits on topics of enzyme catalysis, synthetic biology, light activated biology and 'proteins' in general. Also demonstrated use of laboratory equipment on lab-tours run for attending students. Event was well received by both students and their teachers and seemed to inspire interest in the subject.

No defined impacts realised to date
Year(s) Of Engagement Activity 2012,2013,2014,2015,2016,2017,2018