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Klebl DP, Aspinall L, Muench SP. Time resolved applications for Cryo-EM; approaches, challenges and future directions. Curr Opin Struct Biol 2023; 83:102696. [PMID: 37716094 DOI: 10.1016/j.sbi.2023.102696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 06/14/2023] [Accepted: 08/14/2023] [Indexed: 09/18/2023]
Abstract
Developments within the cryo-EM field have allowed us to generate higher-resolution "static" structures and pull out different conformational states which exist at equilibrium within the sample. Moreover, to trap non-equilibrium states and determine conformations that are present after a defined period of time (typically in the ms time frame) new approaches have been developed for the application of time-resolved cryo-EM. Here we give an overview of these different approaches and the limitations and strengths of each whilst identifying some of the current challenges to achieve higher resolutions and trap states within faster time frames. Time-resolved applications may play an important role in the ever-expanding toolkit of cryo-EM and open up new possibilities in both single particle and tomographic studies.
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Affiliation(s)
- David P Klebl
- School of Biomedical Sciences, Astbury Centre for Structural Molecular Biology, University of Leeds, UK
| | - Louie Aspinall
- School of Molecular and Cellular Biology, University of Leeds, UK
| | - Stephen P Muench
- School of Biomedical Sciences, Astbury Centre for Structural Molecular Biology, University of Leeds, UK.
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2
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Hagen WR. The Development of Tungsten Biochemistry-A Personal Recollection. Molecules 2023; 28:molecules28104017. [PMID: 37241758 DOI: 10.3390/molecules28104017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/27/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
The development of tungsten biochemistry is sketched from the viewpoint of personal participation. Following its identification as a bio-element, a catalogue of genes, enzymes, and reactions was built up. EPR spectroscopic monitoring of redox states was, and remains, a prominent tool in attempts to understand tungstopterin-based catalysis. A paucity of pre-steady-state data remains a hindrance to overcome to this day. Tungstate transport systems have been characterized and found to be very specific for W over Mo. Additional selectivity is presented by the biosynthetic machinery for tungstopterin enzymes. Metallomics analysis of hyperthermophilic archaeon Pyrococcus furiosus indicates a comprehensive inventory of tungsten proteins.
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Affiliation(s)
- Wilfred R Hagen
- Department of Biotechnology, Delft University of Technology, Building 58, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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3
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Vasina M, Kovar D, Damborsky J, Ding Y, Yang T, deMello A, Mazurenko S, Stavrakis S, Prokop Z. In-depth analysis of biocatalysts by microfluidics: An emerging source of data for machine learning. Biotechnol Adv 2023; 66:108171. [PMID: 37150331 DOI: 10.1016/j.biotechadv.2023.108171] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 05/04/2023] [Accepted: 05/04/2023] [Indexed: 05/09/2023]
Abstract
Nowadays, the vastly increasing demand for novel biotechnological products is supported by the continuous development of biocatalytic applications which provide sustainable green alternatives to chemical processes. The success of a biocatalytic application is critically dependent on how quickly we can identify and characterize enzyme variants fitting the conditions of industrial processes. While miniaturization and parallelization have dramatically increased the throughput of next-generation sequencing systems, the subsequent characterization of the obtained candidates is still a limiting process in identifying the desired biocatalysts. Only a few commercial microfluidic systems for enzyme analysis are currently available, and the transformation of numerous published prototypes into commercial platforms is still to be streamlined. This review presents the state-of-the-art, recent trends, and perspectives in applying microfluidic tools in the functional and structural analysis of biocatalysts. We discuss the advantages and disadvantages of available technologies, their reproducibility and robustness, and readiness for routine laboratory use. We also highlight the unexplored potential of microfluidics to leverage the power of machine learning for biocatalyst development.
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Affiliation(s)
- Michal Vasina
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, 602 00 Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, 656 91 Brno, Czech Republic
| | - David Kovar
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, 602 00 Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, 656 91 Brno, Czech Republic
| | - Jiri Damborsky
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, 602 00 Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, 656 91 Brno, Czech Republic
| | - Yun Ding
- Institute for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Tianjin Yang
- Institute for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland; Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Andrew deMello
- Institute for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland
| | - Stanislav Mazurenko
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, 602 00 Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, 656 91 Brno, Czech Republic.
| | - Stavros Stavrakis
- Institute for Chemical and Bioengineering, ETH Zürich, 8093 Zürich, Switzerland.
| | - Zbynek Prokop
- Loschmidt Laboratories, Department of Experimental Biology and RECETOX, Faculty of Science, Masaryk University, 602 00 Brno, Czech Republic; International Clinical Research Centre, St. Anne's University Hospital, 656 91 Brno, Czech Republic.
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4
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Mizukami T, Roder H. Advances in Mixer Design and Detection Methods for Kinetics Studies of Macromolecular Folding and Binding on the Microsecond Time Scale. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27113392. [PMID: 35684328 PMCID: PMC9182321 DOI: 10.3390/molecules27113392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/20/2022] [Accepted: 05/21/2022] [Indexed: 11/16/2022]
Abstract
Many important biological processes such as protein folding and ligand binding are too fast to be fully resolved using conventional stopped-flow techniques. Although advances in mixer design and detection methods have provided access to the microsecond time regime, there is room for improvement in terms of temporal resolution and sensitivity. To address this need, we developed a continuous-flow mixing instrument with a dead time of 12 to 27 µs (depending on solution viscosity) and enhanced sensitivity, sufficient for monitoring tryptophan or tyrosine fluorescence changes at fluorophore concentrations as low as 1 µM. Relying on commercially available laser microfabrication services, we obtained an integrated mixer/flow-cell assembly on a quartz chip, based on a cross-channel configuration with channel dimensions and geometry designed to minimize backpressure. By gradually increasing the width of the observation channel downstream from the mixing region, we are able to monitor a reaction progress time window ranging from ~10 µs out to ~3 ms. By combining a solid-state UV laser with a Galvano-mirror scanning strategy, we achieved highly efficient and uniform fluorescence excitation along the flow channel. Examples of applications, including refolding of acid-denatured cytochrome c triggered by a pH jump and binding of a peptide ligand to a PDZ domain, demonstrate the capability of the technique to resolve fluorescence changes down to the 10 µs time regime on modest amounts of reagents.
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Püschmann J, Mahor D, de Geus DC, Strampraad MJF, Srour B, Hagen WR, Todorovic S, Hagedoorn PL. Unique Biradical Intermediate in the Mechanism of the Heme Enzyme Chlorite Dismutase. ACS Catal 2021; 11:14533-14544. [PMID: 34888122 PMCID: PMC8650003 DOI: 10.1021/acscatal.1c03432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/04/2021] [Indexed: 11/30/2022]
Abstract
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The heme enzyme chlorite
dismutase (Cld) catalyzes O–O bond
formation as part of the conversion of the toxic chlorite (ClO2–) to chloride (Cl–) and
molecular oxygen (O2). Enzymatic O–O bond formation
is rare in nature, and therefore, the reaction mechanism of Cld is
of great interest. Microsecond timescale pre-steady-state kinetic
experiments employing Cld from Azospira oryzae (AoCld), the natural substrate chlorite, and the
model substrate peracetic acid (PAA) reveal the formation of distinct
intermediates. AoCld forms a complex with PAA rapidly,
which is cleaved heterolytically to yield Compound I, which is sequentially
converted to Compound II. In the presence of chlorite, AoCld forms an initial intermediate with spectroscopic characteristics
of a 6-coordinate high-spin ferric substrate adduct, which subsequently
transforms at kobs = 2–5 ×
104 s–1 to an intermediate 5-coordinated
high-spin ferric species. Microsecond-timescale freeze-hyperquench
experiments uncovered the presence of a transient low-spin ferric
species and a triplet species attributed to two weakly coupled amino
acid cation radicals. The intermediates of the chlorite reaction were
not observed with the model substrate PAA. These findings demonstrate
the nature of physiologically relevant catalytic intermediates and
show that the commonly used model substrate may not behave as expected,
which demands a revision of the currently proposed mechanism of Clds.
The transient triplet-state biradical species that we designate as
Compound T is, to the best of our knowledge, unique in heme enzymology.
The results highlight electron paramagnetic resonance spectroscopic
evidence for transient intermediate formation during the reaction
of AoCld with its natural substrate chlorite. In
the proposed mechanism, the heme iron remains ferric throughout the
catalytic cycle, which may minimize the heme moiety’s reorganization
and thereby maximize the enzyme’s catalytic efficiency.
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Affiliation(s)
- Julia Püschmann
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Durga Mahor
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Daniël C. de Geus
- Janssen Vaccines & Prevention, Archimedesweg 4-6, 2333 CN Leiden, The Netherlands
| | - Marc J. F. Strampraad
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Batoul Srour
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Wilfred R. Hagen
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
| | - Smilja Todorovic
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Peter-Leon Hagedoorn
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands
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Ma C, Sun X, Kong L, Wang X, Zhou S, Wei X, Kirsanov D, Legin A, Wan H, Wang P. A multi-channel handheld automatic spectrometer for wide range and on-site detection of okadaic acid based on specific aptamer binding. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2021; 13:4345-4353. [PMID: 34622887 DOI: 10.1039/d1ay00976a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Okadaic acid (OA) is one of the marine toxins that are widely distributed and harmful to humans. However, the current detection methods for OA involve complex procedures, need long detection time, and rely on large-scale laboratory equipment. In this work, a multi-channel handheld automatic spectrometer (MHAS) based on a spectral sensor was developed with the advantages of small size, simple operation and low cost. It could achieve rapid detection within 30 s and a wide spectral detection range of 470-780 nm with a broadband LED as the light source and a microplate containing 8 wells as a sample cell. Moreover, through the combination of gold nanoparticles (AuNPs) and aptamer-OA34, a highly sensitive and rapid system for OA detection was established with a LOD of 1.80 μg L-1 and a wide detection range of 20-10 000 μg L-1, which is comparable to a microplate reader. Compared with other studies, the proposed MHAS realized rapid on-site detection of OA with a wider detection range, shorter detection time and higher portability. Therefore, the MHAS promises to be a stable and efficient optical detection instrument for on-site detection in the fields of food safety, disease diagnosis and environmental monitoring.
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Affiliation(s)
- Chiyu Ma
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Xianyou Sun
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Liubing Kong
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Xinyi Wang
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Shuqi Zhou
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Xinwei Wei
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Dmitry Kirsanov
- Laboratory of Chemical Sensors, Chemistry Department, Saint-Petersburg State University, 199034, Russia
| | - Andrey Legin
- Laboratory of Chemical Sensors, Chemistry Department, Saint-Petersburg State University, 199034, Russia
| | - Hao Wan
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Ping Wang
- Biosensor National Special Laboratory, Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, Zhejiang University, Hangzhou, 310027, China.
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Ash PA, Kendall-Price SET, Vincent KA. Unifying Activity, Structure, and Spectroscopy of [NiFe] Hydrogenases: Combining Techniques To Clarify Mechanistic Understanding. Acc Chem Res 2019; 52:3120-3131. [PMID: 31675209 DOI: 10.1021/acs.accounts.9b00293] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Achieving a unified understanding of the mechanism of a multicenter redox enzyme such as [NiFe] hydrogenase is complicated by difficulties in reconciling information obtained by using different techniques and on samples in different physical forms. Measurements of the activity of the enzyme, and of factors which perturb activity, are generally carried out using biochemical assays in solution or with electrode-immobilized enzymes using protein film electrochemistry (PFE). Conversely, spectroscopy aimed at reporting on features of the metalloclusters in the enzyme, such as electron paramagnetic resonance (EPR) or X-ray absorption spectroscopy (XAS), is often conducted on frozen samples and is thus difficult to relate to catalytically relevant states as information about turnover and activity has been lost. To complicate matters further, most of our knowledge of the atomic-level structure of metalloenzymes comes from X-ray diffraction studies in the solid, crystalline state, which are again difficult to link to turnover conditions. Taking [NiFe] hydrogenases as our case study, we show here how it is possible to apply infrared (IR) spectroscopic sampling approaches to unite direct spectroscopic study with catalytic turnover. Using a method we have named protein film IR electrochemistry (PFIRE), we reveal the steady-state distribution of intermediates during catalysis and identify catalytic "bottlenecks" introduced by site-directed mutagenesis. We also show that it is possible to study dynamic transitions between active site states of enzymes in single crystals, uniting solid state and solution spectroscopic information. In all of these cases, the spectroscopic data complement and enhance interpretation of purely activity-based measurements by providing direct chemical insight that is otherwise hidden. The [NiFe] hydrogenases possess a bimetallic [NiFe] active site, coordinated by CO and CN- ligands, linked to the protein via bridging and terminal cysteine sulfur ligands, as well as an electron relay chain of iron sulfur clusters. Infrared spectroscopy is ideal for probing hydrogenases because the CO and CN- ligands are strong IR absorbers, but the suite of IR-based approaches we describe here will be equally valuable in studying substrate- or intermediate-bound states of other metalloenzymes where key mechanistic questions remain open, such as nitrogenase, formate dehydrogenase, or carbon monoxide dehydrogenase. We therefore hope that this Account will encourage future studies which unify information from different techniques across bioinorganic chemistry.
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Affiliation(s)
- Philip A. Ash
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
- School of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
| | | | - Kylie A. Vincent
- Department of Chemistry, University of Oxford, Oxford OX1 3QR, United Kingdom
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8
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Refolding kinetics of cytochrome c studied with microsecond timescale continuous-flow UV–vis spectroscopy and rapid freeze-quench EPR. J Inorg Biochem 2018; 184:42-49. [DOI: 10.1016/j.jinorgbio.2018.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/21/2018] [Accepted: 04/09/2018] [Indexed: 11/18/2022]
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