1
|
Brinatti Vazquez GD, Lo Gerfo Morganti G, Vasilev C, Hunter CN, van Hulst NF. Structured Excitation Energy Transfer: Tracking Exciton Diffusion below Sunlight Intensity. ACS Photonics 2024; 11:1318-1326. [PMID: 38523751 PMCID: PMC10958594 DOI: 10.1021/acsphotonics.4c00004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/09/2024] [Accepted: 02/12/2024] [Indexed: 03/26/2024]
Abstract
With the increasing demand for new materials for light-harvesting applications, spatiotemporal microscopy techniques are receiving increasing attention as they allow direct observation of the nanoscale diffusion of excitons. However, the use of pulsed and tightly focused laser beams generates light intensities far above those expected under sunlight illumination, leading to photodamage and nonlinear effects that seriously limit the accuracy and applicability of these techniques, especially in biological or atomically thin materials. In this work, we present a novel spatiotemporal microscopy technique that exploits structured excitation in order to dramatically decrease the excitation intensity, up to 10,000-fold when compared with previously reported spatiotemporal photoluminescence microscopy experiments. We tested our method in two different systems, reporting the first exciton diffusion measurement at illumination conditions below sunlight, both considering average power and peak exciton densities in an organic photovoltaic sample (Y6), where we tracked the excitons for up to five recombination lifetimes. Next, nanometer-scale energy transport was directly observed for the first time in both space and time in a printed monolayer of the light-harvesting complex 2 from purple bacteria.
Collapse
Affiliation(s)
- Guillermo D. Brinatti Vazquez
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Giulia Lo Gerfo Morganti
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
| | - Cvetelin Vasilev
- School
of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K.
| | - C. Neil Hunter
- School
of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K.
| | - Niek F. van Hulst
- ICFO-Institut
de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, Barcelona 08860, Spain
- ICREA-Institució
Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, Barcelona 08010, Spain
| |
Collapse
|
2
|
Huang X, Vasilev C, Swainsbury D, Hunter C. Excitation energy transfer in proteoliposomes reconstituted with LH2 and RC-LH1 complexes from Rhodobacter sphaeroides. Biosci Rep 2024; 44:BSR20231302. [PMID: 38227291 PMCID: PMC10876425 DOI: 10.1042/bsr20231302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/30/2023] [Accepted: 01/16/2024] [Indexed: 01/17/2024] Open
Abstract
Light-harvesting 2 (LH2) and reaction-centre light-harvesting 1 (RC-LH1) complexes purified from the photosynthetic bacterium Rhodobacter (Rba.) sphaeroides were reconstituted into proteoliposomes either separately, or together at three different LH2:RC-LH1 ratios, for excitation energy transfer studies. Atomic force microscopy (AFM) was used to investigate the distribution and association of the complexes within the proteoliposome membranes. Absorption and fluorescence emission spectra were similar for LH2 complexes in detergent and liposomes, indicating that reconstitution retains the structural and optical properties of the LH2 complexes. Analysis of fluorescence emission shows that when LH2 forms an extensive series of contacts with other such complexes, fluorescence is quenched by 52.6 ± 1.4%. In mixed proteoliposomes, specific excitation of carotenoids in LH2 donor complexes resulted in emission of fluorescence from acceptor RC-LH1 complexes engineered to assemble with no carotenoids. Extents of energy transfer were measured by fluorescence lifetime microscopy; the 0.72 ± 0.08 ns lifetime in LH2-only membranes decreases to 0.43 ± 0.04 ns with a ratio of 2:1 LH2 to RC-LH1, and to 0.35 ± 0.05 ns for a 1:1 ratio, corresponding to energy transfer efficiencies of 40 ± 14% and 51 ± 18%, respectively. No further improvement is seen with a 0.5:1 LH2 to RC-LH1 ratio. Thus, LH2 and RC-LH1 complexes perform their light harvesting and energy transfer roles when reconstituted into proteoliposomes, providing a way to integrate native, non-native, engineered and de novo designed light-harvesting complexes into functional photosynthetic systems.
Collapse
Affiliation(s)
- Xia Huang
- Department of Biological Sciences, Xi’an Jiaotong-Liverpool University, Suzhou, Jiangsu 215123, China
- Jinan Guoke Medical Technology Development Co., Ltd, Jinan, Shandong 250101, China
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - Cvetelin Vasilev
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| | - David J.K. Swainsbury
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, U.K
| | - C. Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, U.K
| |
Collapse
|
3
|
Ennist N, Wang S, Kennedy M, Curti M, Sutherland G, Vasilev C, Redler R, Maffeis V, Shareef S, Sica A, Hua A, Deshmukh A, Moyer A, Hicks D, Swartz A, Cacho R, Novy N, Bera A, Kang A, Sankaran B, Johnson M, Reppert M, Ekiert D, Bhabha G, Stewart L, Caram J, Stoddard B, Romero E, Hunter CN, Baker D. De novo design of energy transfer proteins housing excitonically coupled chlorophyll special pairs. Res Sq 2023:rs.3.rs-2736786. [PMID: 37131790 PMCID: PMC10153362 DOI: 10.21203/rs.3.rs-2736786/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Natural photosystems couple light harvesting to charge separation using a "special pair" of chlorophyll molecules that accepts excitation energy from the antenna and initiates an electron-transfer cascade. To investigate the photophysics of special pairs independent of complexities of native photosynthetic proteins, and as a first step towards synthetic photosystems for new energy conversion technologies, we designed C2-symmetric proteins that precisely position chlorophyll dimers. X-ray crystallography shows that one designed protein binds two chlorophylls in a binding orientation matching native special pairs, while a second positions them in a previously unseen geometry. Spectroscopy reveals excitonic coupling, and fluorescence lifetime imaging demonstrates energy transfer. We designed special pair proteins to assemble into 24-chlorophyll octahedral nanocages; the design model and cryo-EM structure are nearly identical. The design accuracy and energy transfer function of these special pair proteins suggest that de novo design of artificial photosynthetic systems is within reach of current computational methods.
Collapse
Affiliation(s)
| | | | | | - Mariano Curti
- Institute of Chemical Research of Catalonia (ICIQ-CERCA)
| | | | | | | | | | - Saeed Shareef
- Institute of Chemical Research of Catalonia (ICIQ-CERCA)
| | | | - Ash Hua
- University of California, Los Angeles
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
4
|
MacGregor-Chatwin C, Nürnberg DJ, Jackson PJ, Vasilev C, Hitchcock A, Ho MY, Shen G, Gisriel CJ, Wood WH, Mahbub M, Selinger VM, Johnson MP, Dickman MJ, Rutherford AW, Bryant DA, Hunter CN. Changes in supramolecular organization of cyanobacterial thylakoid membrane complexes in response to far-red light photoacclimation. Sci Adv 2022; 8:eabj4437. [PMID: 35138895 PMCID: PMC8827656 DOI: 10.1126/sciadv.abj4437] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 12/15/2021] [Indexed: 06/14/2023]
Abstract
Cyanobacteria are ubiquitous in nature and have developed numerous strategies that allow them to live in a diverse range of environments. Certain cyanobacteria synthesize chlorophylls d and f to acclimate to niches enriched in far-red light (FRL) and incorporate paralogous photosynthetic proteins into their photosynthetic apparatus in a process called FRL-induced photoacclimation (FaRLiP). We characterized the macromolecular changes involved in FRL-driven photosynthesis and used atomic force microscopy to examine the supramolecular organization of photosystem I associated with FaRLiP in three cyanobacterial species. Mass spectrometry showed the changes in the proteome of Chroococcidiopsis thermalis PCC 7203 that accompany FaRLiP. Fluorescence lifetime imaging microscopy and electron microscopy reveal an altered cellular distribution of photosystem complexes and illustrate the cell-to-cell variability of the FaRLiP response.
Collapse
Affiliation(s)
| | - Dennis J. Nürnberg
- Department of Life Sciences, Imperial College London, London, UK
- Physics Department, Freie Universität Berlin, Berlin, Germany
| | - Philip J. Jackson
- School of Biosciences, University of Sheffield, Sheffield, UK
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | | | | | - Ming-Yang Ho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Christopher J. Gisriel
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, AZ, USA
| | | | - Moontaha Mahbub
- Department of Life Sciences, Imperial College London, London, UK
| | | | | | - Mark J. Dickman
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | | | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - C. Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield, UK
| |
Collapse
|
5
|
Vasilev C, Swainsbury DJK, Cartron ML, Martin EC, Kumar S, Hobbs JK, Johnson MP, Hitchcock A, Hunter CN. FRET measurement of cytochrome bc 1 and reaction centre complex proximity in live Rhodobacter sphaeroides cells. Biochim Biophys Acta Bioenerg 2021; 1863:148508. [PMID: 34793767 DOI: 10.1016/j.bbabio.2021.148508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 10/27/2021] [Accepted: 11/09/2021] [Indexed: 11/30/2022]
Abstract
In the model purple phototrophic bacterium Rhodobacter (Rba.) sphaeroides, solar energy is converted via coupled electron and proton transfer reactions within the intracytoplasmic membranes (ICMs), infoldings of the cytoplasmic membrane that form spherical 'chromatophore' vesicles. These bacterial 'organelles' are ideal model systems for studying how the organisation of the photosynthetic complexes therein shape membrane architecture. In Rba. sphaeroides, light-harvesting 2 (LH2) complexes transfer absorbed excitation energy to dimeric reaction centre (RC)-LH1-PufX complexes. The PufX polypeptide creates a channel that allows the lipid soluble electron carrier quinol, produced by RC photochemistry, to diffuse to the cytochrome bc1 complex, where quinols are oxidised to quinones, with the liberated protons used to generate a transmembrane proton gradient and the electrons returned to the RC via cytochrome c2. Proximity between cytochrome bc1 and RC-LH1-PufX minimises quinone/quinol/cytochrome c2 diffusion distances within this protein-crowded membrane, however this distance has not yet been measured. Here, we tag the RC and cytochrome bc1 with yellow or cyan fluorescent proteins (YFP/CFP) and record the lifetimes of YFP/CFP Förster resonance energy transfer (FRET) pairs in whole cells. FRET analysis shows that that these complexes lie on average within 6 nm of each other. Complementary high-resolution atomic force microscopy (AFM) of intact, purified chromatophores verifies the close association of cytochrome bc1 complexes with RC-LH1-PufX dimers. Our results provide a structural basis for the close kinetic coupling between RC-LH1-PufX and cytochrome bc1 observed by spectroscopy, and explain how quinols/quinones and cytochrome c2 shuttle on a millisecond timescale between these complexes, sustaining efficient photosynthetic electron flow.
Collapse
Affiliation(s)
- Cvetelin Vasilev
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom.
| | - David J K Swainsbury
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Michael L Cartron
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Elizabeth C Martin
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Sandip Kumar
- Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7HR, United Kingdom; Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Jamie K Hobbs
- Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7HR, United Kingdom
| | - Matthew P Johnson
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - Andrew Hitchcock
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - C Neil Hunter
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| |
Collapse
|
6
|
Huang X, Vasilev C, Hunter CN. Excitation energy transfer between monomolecular layers of light harvesting LH2 and LH1-reaction centre complexes printed on a glass substrate. Lab Chip 2020; 20:2529-2538. [PMID: 32662473 DOI: 10.1039/d0lc00156b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Light-harvesting 2 (LH2) and light-harvesting 1 - reaction centre (RCLH1) complexes purified from the photosynthetic bacterium Rhodobacter (Rba.) sphaeroides were cross-patterned on glass surfaces for energy transfer studies. Atomic force microscopy (AFM) images of the RCLH1 and LH2 patterns show the deposition of monomolecular layers of complexes on the glass substrate. Spectral imaging and fluorescence life-time imaging microscopy (FLIM) revealed that RCLH1 and LH2 complexes, sealed under physiological conditions, retained their native light-harvesting and energy transfer functions. Measurements of the amplitude and lifetime decay of fluorescence emission from LH2 complexes, the energy transfer donors, and gain of fluorescence emission from acceptor RCLH1 complexes, provide evidence for excitation energy transfer from LH2 to RCLH1. Directional energy transfer on the glass substrate was unequivocally established by using LH2-carotenoid complexes and RCLH1 complexes with genetically removed carotenoids. Specific excitation of carotenoids in donor LH2 complexes elicited fluorescence emission from RCLH1 acceptors. To explore the longevity of this novel nanoprinted photosynthetic unit, RCLH1 and LH2 complexes were cross-patterned on a glass surface and sealed under a protective argon atmosphere. The results show that both complexes retained their individual and collective functions and are capable of directional excitation energy transfer for at least 60 days.
Collapse
Affiliation(s)
- Xia Huang
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
| | | | | |
Collapse
|
7
|
Burg SL, Washington A, Coles DM, Bianco A, McLoughlin D, Mykhaylyk OO, Villanova J, Dennison AJC, Hill CJ, Vukusic P, Doak S, Martin SJ, Hutchings M, Parnell SR, Vasilev C, Clarke N, Ryan AJ, Furnass W, Croucher M, Dalgliesh RM, Prevost S, Dattani R, Parker A, Jones RAL, Fairclough JPA, Parnell AJ. Liquid–liquid phase separation morphologies in ultra-white beetle scales and a synthetic equivalent. Commun Chem 2019. [DOI: 10.1038/s42004-019-0202-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
|
8
|
Lishchuk A, Vasilev C, Johnson MP, Hunter CN, Törmä P, Leggett GJ. Turning the challenge of quantum biology on its head: biological control of quantum optical systems. Faraday Discuss 2019; 216:57-71. [PMID: 31016297 DOI: 10.1039/c8fd00241j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
When light-harvesting complex II (LHCII), isolated from spinach, is adsorbed onto arrays of gold nanostructures formed by interferometric lithography, a pronounced splitting of the plasmon band is observed that is attributable to strong coupling of the localised surface plasmon resonance to excitons in the pigment-protein complex. The system is modelled as coupled harmonic oscillators, yielding an exciton energy of 2.24 ± 0.02 eV. Analysis of dispersion curves yields a Rabi energy of 0.25 eV. Extinction spectra of the strongly coupled system yield a resonance at 1.43 eV that varies as a function of the density of nanostructures in the array. The enhanced intensity of this feature is attributed to strong plasmon-exciton coupling. Comparison of data for a large number of light-harvesting complexes indicates that by control of the protein structure and/or pigment compliment it is possible to manipulate the strength of plasmon-exciton coupling. In strongly coupled systems, ultra-fast exchange of energy occurs between pigment molecules: coherent coupling between non-local excitons can be manipulated via selection of the protein structure enabling the observation of transitions that are not seen in the weak coupling regime. Synthetic biology thus provides a means to control quantum-optical interactions in the strong coupling regime.
Collapse
Affiliation(s)
- Anna Lishchuk
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK.
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Päivi Törmä
- Department of Applied Physics, Aalto University, School of Science, P.O. Box 15100, 00076 Aalto, Finland
| | - Graham J Leggett
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK.
| |
Collapse
|
9
|
Adams PG, Vasilev C, Hunter CN, Johnson MP. Correlated fluorescence quenching and topographic mapping of Light-Harvesting Complex II within surface-assembled aggregates and lipid bilayers. Biochim Biophys Acta Bioenerg 2018; 1859:1075-1085. [PMID: 29928860 PMCID: PMC6135645 DOI: 10.1016/j.bbabio.2018.06.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 06/11/2018] [Accepted: 06/15/2018] [Indexed: 01/30/2023]
Abstract
Light-Harvesting Complex II (LHCII) is a chlorophyll-protein antenna complex that efficiently absorbs solar energy and transfers electronic excited states to photosystems I and II. Under excess light intensity LHCII can adopt a photoprotective state in which excitation energy is safely dissipated as heat, a process known as Non-Photochemical Quenching (NPQ). In vivo NPQ is triggered by combinatorial factors including transmembrane ΔpH, PsbS protein and LHCII-bound zeaxanthin, leading to dramatically shortened LHCII fluorescence lifetimes. In vitro, LHCII in detergent solution or in proteoliposomes can reversibly adopt an NPQ-like state, via manipulation of detergent/protein ratio, lipid/protein ratio, pH or pressure. Previous spectroscopic investigations revealed changes in exciton dynamics and protein conformation that accompany quenching, however, LHCII-LHCII interactions have not been extensively studied. Here, we correlated fluorescence lifetime imaging microscopy (FLIM) and atomic force microscopy (AFM) of trimeric LHCII adsorbed to mica substrates and manipulated the environment to cause varying degrees of quenching. AFM showed that LHCII self-assembled onto mica forming 2D-aggregates (25-150 nm width). FLIM determined that LHCII in these aggregates were in a quenched state, with much lower fluorescence lifetimes (~0.25 ns) compared to free LHCII in solution (2.2-3.9 ns). LHCII-LHCII interactions were disrupted by thylakoid lipids or phospholipids, leading to intermediate fluorescent lifetimes (0.6-0.9 ns). To our knowledge, this is the first in vitro correlation of nanoscale membrane imaging with LHCII quenching. Our findings suggest that lipids could play a key role in modulating the extent of LHCII-LHCII interactions within the thylakoid membrane and so the propensity for NPQ activation.
Collapse
Affiliation(s)
- Peter G Adams
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| |
Collapse
|
10
|
Chen GE, Canniffe DP, Barnett SFH, Hollingshead S, Brindley AA, Vasilev C, Bryant DA, Hunter CN. Complete enzyme set for chlorophyll biosynthesis in Escherichia coli. Sci Adv 2018; 4:eaaq1407. [PMID: 29387799 PMCID: PMC5787379 DOI: 10.1126/sciadv.aaq1407] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/28/2017] [Indexed: 05/08/2023]
Abstract
Chlorophylls are essential cofactors for photosynthesis, which sustains global food chains and oxygen production. Billions of tons of chlorophylls are synthesized annually, yet full understanding of chlorophyll biosynthesis has been hindered by the lack of characterization of the Mg-protoporphyrin IX monomethyl ester oxidative cyclase step, which confers the distinctive green color of these pigments. We demonstrate cyclase activity using heterologously expressed enzyme. Next, we assemble a genetic module that encodes the complete chlorophyll biosynthetic pathway and show that it functions in Escherichia coli. Expression of 12 genes converts endogenous protoporphyrin IX into chlorophyll a, turning E. coli cells green. Our results delineate a minimum set of enzymes required to make chlorophyll and establish a platform for engineering photosynthesis in a heterotrophic model organism.
Collapse
Affiliation(s)
- Guangyu E. Chen
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Daniel P. Canniffe
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Samuel F. H. Barnett
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Sarah Hollingshead
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Amanda A. Brindley
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - C. Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| |
Collapse
|
11
|
Swainsbury DJK, Martin EC, Vasilev C, Parkes-Loach PS, Loach PA, Neil Hunter C. Engineering of a calcium-ion binding site into the RC-LH1-PufX complex of Rhodobacter sphaeroides to enable ion-dependent spectral red-shifting. Biochim Biophys Acta Bioenerg 2017; 1858:927-938. [PMID: 28826909 PMCID: PMC5604489 DOI: 10.1016/j.bbabio.2017.08.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/02/2017] [Accepted: 08/17/2017] [Indexed: 01/01/2023]
Abstract
The reaction centre-light harvesting 1 (RC-LH1) complex of Thermochromatium (Tch.) tepidum has a unique calcium-ion binding site that enhances thermal stability and red-shifts the absorption of LH1 from 880nm to 915nm in the presence of calcium-ions. The LH1 antenna of mesophilic species of phototrophic bacteria such as Rhodobacter (Rba.) sphaeroides does not possess such properties. We have engineered calcium-ion binding into the LH1 antenna of Rba. sphaeroides by progressively modifying the native LH1 polypeptides with sequences from Tch. tepidum. We show that acquisition of the C-terminal domains from LH1 α and β of Tch. tepidum is sufficient to activate calcium-ion binding and the extent of red-shifting increases with the proportion of Tch. tepidum sequence incorporated. However, full exchange of the LH1 polypeptides with those of Tch. tepidum results in misassembled core complexes. Isolated α and β polypeptides from our most successful mutant were reconstituted in vitro with BChl a to form an LH1-type complex, which was stabilised 3-fold by calcium-ions. Additionally, carotenoid specificity was changed from spheroidene found in Rba. sphaeroides to spirilloxanthin found in Tch. tepidum, with the latter enhancing in vitro formation of LH1. These data show that the C-terminal LH1 α/β domains of Tch. tepidum behave autonomously, and are able to transmit calcium-ion induced conformational changes to BChls bound to the rest of a foreign antenna complex. Thus, elements of foreign antenna complexes, such as calcium-ion binding and blue/red switching of absorption, can be ported into Rhodobacter sphaeroides using careful design processes.
Collapse
Affiliation(s)
- David J K Swainsbury
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom.
| | - Elizabeth C Martin
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom
| | - Pamela S Parkes-Loach
- Department of Molecular Biosciences, Northwestern University, Hogan 2100, 2205 Tech Drive, Evanston, IL 60208, United States
| | - Paul A Loach
- Department of Molecular Biosciences, Northwestern University, Hogan 2100, 2205 Tech Drive, Evanston, IL 60208, United States
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, United Kingdom
| |
Collapse
|
12
|
Tsargorodska A, Cartron ML, Vasilev C, Kodali G, Mass OA, Baumberg JJ, Dutton PL, Hunter CN, Törmä P, Leggett GJ. Strong Coupling of Localized Surface Plasmons to Excitons in Light-Harvesting Complexes. Nano Lett 2016; 16:6850-6856. [PMID: 27689237 PMCID: PMC5135229 DOI: 10.1021/acs.nanolett.6b02661] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/28/2016] [Indexed: 05/24/2023]
Abstract
Gold nanostructure arrays exhibit surface plasmon resonances that split after attaching light harvesting complexes 1 and 2 (LH1 and LH2) from purple bacteria. The splitting is attributed to strong coupling between the localized surface plasmon resonances and excitons in the light-harvesting complexes. Wild-type and mutant LH1 and LH2 from Rhodobacter sphaeroides containing different carotenoids yield different splitting energies, demonstrating that the coupling mechanism is sensitive to the electronic states in the light harvesting complexes. Plasmon-exciton coupling models reveal different coupling strengths depending on the molecular organization and the protein coverage, consistent with strong coupling. Strong coupling was also observed for self-assembling polypeptide maquettes that contain only chlorins. However, it is not observed for monolayers of bacteriochlorophyll, indicating that strong plasmon-exciton coupling is sensitive to the specific presentation of the pigment molecules.
Collapse
Affiliation(s)
- Anna Tsargorodska
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K.
| | - Michaël L. Cartron
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, U.K.
| | - Cvetelin Vasilev
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, U.K.
| | - Goutham Kodali
- The
Johnson Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 10104, United States
| | - Olga A. Mass
- Department
of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Jeremy J. Baumberg
- Cavendish
Laboratory, Dept. of Physics, University
of Cambridge, J. J. Thomson
Ave, Cambridge, CB3 0HE, U.K.
| | - P. Leslie Dutton
- The
Johnson Research Foundation and Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 10104, United States
| | - C. Neil Hunter
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, U.K.
| | - Päivi Törmä
- COMP Centre
of Excellence, Department of Applied Physics, Aalto University, School of Science,
P.O. Box 15100, 00076 Aalto, Finland
| | - Graham J. Leggett
- Department
of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, U.K.
| |
Collapse
|
13
|
Adams NBP, Vasilev C, Brindley AA, Hunter CN. Nanomechanical and Thermophoretic Analyses of the Nucleotide-Dependent Interactions between the AAA(+) Subunits of Magnesium Chelatase. J Am Chem Soc 2016; 138:6591-7. [PMID: 27133226 PMCID: PMC4882731 DOI: 10.1021/jacs.6b02827] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In chlorophyll biosynthesis, the magnesium chelatase enzyme complex catalyzes the insertion of a Mg(2+) ion into protoporphyrin IX. Prior to this event, two of the three subunits, the AAA(+) proteins ChlI and ChlD, form a ChlID-MgATP complex. We used microscale thermophoresis to directly determine dissociation constants for the I-D subunits from Synechocystis, and to show that the formation of a ChlID-MgADP complex, mediated by the arginine finger and the sensor II domain on ChlD, is necessary for the assembly of the catalytically active ChlHID-MgATP complex. The N-terminal AAA(+) domain of ChlD is essential for complex formation, but some stability is preserved in the absence of the C-terminal integrin domain of ChlD, particularly if the intervening polyproline linker region is retained. Single molecule force spectroscopy (SMFS) was used to determine the factors that stabilize formation of the ChlID-MgADP complex at the single molecule level; ChlD was attached to an atomic force microscope (AFM) probe in two different orientations, and the ChlI subunits were tethered to a silica surface; the probability of subunits interacting more than doubled in the presence of MgADP, and we show that the N-terminal AAA(+) domain of ChlD mediates this process, in agreement with the microscale thermophoresis data. Analysis of the unbinding data revealed a most probable interaction force of around 109 pN for formation of single ChlID-MgADP complexes. These experiments provide a quantitative basis for understanding the assembly and function of the Mg chelatase complex.
Collapse
Affiliation(s)
- Nathan B P Adams
- Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield S10 2TN, United Kingdom
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield S10 2TN, United Kingdom
| | - Amanda A Brindley
- Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield S10 2TN, United Kingdom
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield S10 2TN, United Kingdom
| |
Collapse
|
14
|
Mothersole DJ, Jackson PJ, Vasilev C, Tucker JD, Brindley AA, Dickman MJ, Hunter CN. PucC and LhaA direct efficient assembly of the light-harvesting complexes in Rhodobacter sphaeroides. Mol Microbiol 2015; 99:307-27. [PMID: 26419219 PMCID: PMC4949548 DOI: 10.1111/mmi.13235] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2015] [Indexed: 01/21/2023]
Abstract
The mature architecture of the photosynthetic membrane of the purple phototroph Rhodobacter sphaeroides has been characterised to a level where an atomic-level membrane model is available, but the roles of the putative assembly proteins LhaA and PucC in establishing this architecture are unknown. Here we investigate the assembly of light-harvesting LH2 and reaction centre-light-harvesting1-PufX (RC-LH1-PufX) photosystem complexes using spectroscopy, pull-downs, native gel electrophoresis, quantitative mass spectrometry and fluorescence lifetime microscopy to characterise a series of lhaA and pucC mutants. LhaA and PucC are important for specific assembly of LH1 or LH2 complexes, respectively, but they are not essential; the few LH1 subunits found in ΔlhaA mutants assemble to form normal RC-LH1-PufX core complexes showing that, once initiated, LH1 assembly round the RC is cooperative and proceeds to completion. LhaA and PucC form oligomers at sites of initiation of membrane invagination; LhaA associates with RCs, bacteriochlorophyll synthase (BchG), the protein translocase subunit YajC and the YidC membrane protein insertase. These associations within membrane nanodomains likely maximise interactions between pigments newly arriving from BchG and nascent proteins within the SecYEG-SecDF-YajC-YidC assembly machinery, thereby co-ordinating pigment delivery, the co-translational insertion of LH polypeptides and their folding and assembly to form photosynthetic complexes.
Collapse
Affiliation(s)
- David J Mothersole
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Philip J Jackson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK.,ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Jaimey D Tucker
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Amanda A Brindley
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| | - Mark J Dickman
- ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
| |
Collapse
|
15
|
Patole S, Vasilev C, El-Zubir O, Wang L, Johnson MP, Cadby AJ, Leggett GJ, Hunter CN. Interference lithographic nanopatterning of plant and bacterial light-harvesting complexes on gold substrates. Interface Focus 2015; 5:20150005. [PMID: 26464784 PMCID: PMC4590419 DOI: 10.1098/rsfs.2015.0005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
We describe a facile approach for nanopatterning of photosynthetic light-harvesting complexes over macroscopic areas, and use optical spectroscopy to demonstrate retention of native properties by both site-specifically and non-specifically attached photosynthetic membrane proteins. A Lloyd's mirror dual-beam interferometer was used to expose self-assembled monolayers of amine-terminated alkylthiolates on gold to laser irradiation. Following exposure, photo-oxidized adsorbates were replaced by oligo(ethylene glycol) terminated thiols, and the remaining intact amine-functionalized regions were used for attachment of the major light-harvesting chlorophyll-protein complex from plants, LHCII. These amine patterns could be derivatized with nitrilotriacetic acid (NTA), so that polyhistidine-tagged bacteriochlorophyll-protein complexes from phototrophic bacteria could be attached with a defined surface orientation. By varying parameters such as the angle between the interfering beams and the laser irradiation dose, it was possible to vary the period and widths of NTA and amine-functionalized lines on the surfaces; periods varied from 1200 to 240 nm and linewidths as small as 60 nm (λ/4) were achieved. This level of control over the surface chemistry was reflected in the surface topology of the protein nanostructures imaged by atomic force microscopy; fluorescence imaging and spectral measurements demonstrated that the surface-attached proteins had retained their native functionality.
Collapse
Affiliation(s)
- Samson Patole
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Osama El-Zubir
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - Lin Wang
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
- Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK
| | - Matthew P. Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Ashley J. Cadby
- Department of Physics and Astronomy, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK
| | - Graham J. Leggett
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK
| | - C. Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| |
Collapse
|
16
|
Chi SC, Mothersole DJ, Dilbeck P, Niedzwiedzki DM, Zhang H, Qian P, Vasilev C, Grayson KJ, Jackson PJ, Martin EC, Li Y, Holten D, Neil Hunter C. Assembly of functional photosystem complexes in Rhodobacter sphaeroides incorporating carotenoids from the spirilloxanthin pathway. Biochim Biophys Acta 2014; 1847:189-201. [PMID: 25449968 PMCID: PMC4331045 DOI: 10.1016/j.bbabio.2014.10.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 10/17/2014] [Accepted: 10/21/2014] [Indexed: 11/29/2022]
Abstract
Carotenoids protect the photosynthetic apparatus against harmful radicals arising from the presence of both light and oxygen. They also act as accessory pigments for harvesting solar energy, and are required for stable assembly of many light-harvesting complexes. In the phototrophic bacterium Rhodobacter (Rba.) sphaeroides phytoene desaturase (CrtI) catalyses three sequential desaturations of the colourless carotenoid phytoene, extending the number of conjugated carbon–carbon double bonds, N, from three to nine and producing the yellow carotenoid neurosporene; subsequent modifications produce the yellow/red carotenoids spheroidene/spheroidenone (N = 10/11). Genomic crtI replacements were used to swap the native three-step Rba. sphaeroides CrtI for the four-step Pantoea agglomerans enzyme, which re-routed carotenoid biosynthesis and culminated in the production of 2,2′-diketo-spirilloxanthin under semi-aerobic conditions. The new carotenoid pathway was elucidated using a combination of HPLC and mass spectrometry. Premature termination of this new pathway by inactivating crtC or crtD produced strains with lycopene or rhodopin as major carotenoids. All of the spirilloxanthin series carotenoids are accepted by the assembly pathways for LH2 and RC–LH1–PufX complexes. The efficiency of carotenoid-to-bacteriochlorophyll energy transfer for 2,2′-diketo-spirilloxanthin (15 conjugated C
Created by potrace 1.16, written by Peter Selinger 2001-2019
]]>C bonds; N = 15) in LH2 complexes is low, at 35%. High energy transfer efficiencies were obtained for neurosporene (N = 9; 94%), spheroidene (N = 10; 96%) and spheroidenone (N = 11; 95%), whereas intermediate values were measured for lycopene (N = 11; 64%), rhodopin (N = 11; 62%) and spirilloxanthin (N = 13; 39%). The variety and stability of these novel Rba. sphaeroides antenna complexes make them useful experimental models for investigating the energy transfer dynamics of carotenoids in bacterial photosynthesis. The spirilloxanthin biosynthetic pathway has been constructed in Rba. sphaeroides. The new carotenoids are accepted by the photosystem assembly pathways. These pigments are efficiently integrated into LH2 and RC–LH1–PufX complexes. Carotenoid–BChl energy transfer drops with the number of conjugated CC bonds (N). The lowest efficiency, 35%, is for the N = 15 carotenoid 2,2′ diketospirilloxanthin.
Collapse
Affiliation(s)
- Shuang C Chi
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - David J Mothersole
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Preston Dilbeck
- Department of Chemistry, Washington University, St. Louis, MO 63130-4889, USA
| | | | - Hao Zhang
- Photosynthetic Antenna Research Center, Washington University, St. Louis, MO 63130 USA
| | - Pu Qian
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Katie J Grayson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Philip J Jackson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom; ChELSI Institute, Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom
| | - Elizabeth C Martin
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Ying Li
- Department of Microbiology and Immunology, China Agricultural University, Haidian District, Beijing 100193, China
| | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, MO 63130-4889, USA
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom.
| |
Collapse
|
17
|
Vasilev C, Johnson MP, Gonzales E, Wang L, Ruban A, Montano G, Cadby AJ, Hunter CN. Reversible switching between nonquenched and quenched states in nanoscale linear arrays of plant light-harvesting antenna complexes. Langmuir 2014; 30:8481-90. [PMID: 24988144 PMCID: PMC4108477 DOI: 10.1021/la501483s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 06/30/2014] [Indexed: 05/23/2023]
Abstract
A simple and robust nanolithographic method that allows sub-100 nm chemical patterning on a range of oxide surfaces was developed in order to fabricate nanoarrays of plant light-harvesting LHCII complexes. The site-specific immobilization and the preserved functionality of the LHCII complexes were confirmed by fluorescence emission spectroscopy. Nanopatterned LHCII trimers could be reversibly switched between fluorescent and quenched states by controlling the detergent concentration in the imaging buffer. A 3-fold quenching of the average fluorescence intensity was accompanied by a decrease in the average (amplitude-weighted) fluorescence lifetime from approximately 2.24 ns to approximately 0.4 ns, attributed to the intrinsic ability of LHCII to switch between fluorescent and quenched states upon changes in its conformational state. The nanopatterning methodology was extended by immobilizing a second protein, the enhanced green fluorescent protein (EGFP), onto LHCII-free areas of the chemically patterned surfaces. This very simple surface chemistry, which allows simultaneous selective immobilization and therefore sorting of the two types of protein molecules on the surface, is a key underpinning step toward the integration of LHCII into switchable biohybrid antenna constructs.
Collapse
Affiliation(s)
- Cvetelin Vasilev
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Matthew P. Johnson
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Edward Gonzales
- Center
for Integrated Nanotechnologies, Los Alamos
National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Lin Wang
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
- Department
of Physics and Astronomy, University of
Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, United Kingdom
| | - Alexander
V. Ruban
- School
of Biological and Chemical Sciences, Queen
Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Gabriel Montano
- Center
for Integrated Nanotechnologies, Los Alamos
National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Ashley J. Cadby
- Department
of Physics and Astronomy, University of
Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, United Kingdom
| | - C. Neil Hunter
- Department
of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom
| |
Collapse
|
18
|
Johnson MP, Vasilev C, Olsen JD, Hunter CN. Nanodomains of cytochrome b6f and photosystem II complexes in spinach grana thylakoid membranes. Plant Cell 2014; 26:3051-61. [PMID: 25035407 PMCID: PMC4145131 DOI: 10.1105/tpc.114.127233] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/06/2014] [Accepted: 06/24/2014] [Indexed: 05/18/2023]
Abstract
The cytochrome b6f (cytb6f) complex plays a central role in photosynthesis, coupling electron transport between photosystem II (PSII) and photosystem I to the generation of a transmembrane proton gradient used for the biosynthesis of ATP. Photosynthesis relies on rapid shuttling of electrons by plastoquinone (PQ) molecules between PSII and cytb6f complexes in the lipid phase of the thylakoid membrane. Thus, the relative membrane location of these complexes is crucial, yet remains unknown. Here, we exploit the selective binding of the electron transfer protein plastocyanin (Pc) to the lumenal membrane surface of the cytb6f complex using a Pc-functionalized atomic force microscope (AFM) probe to identify the position of cytb6f complexes in grana thylakoid membranes from spinach (Spinacia oleracea). This affinity-mapping AFM method directly correlates membrane surface topography with Pc-cytb6f interactions, allowing us to construct a map of the grana thylakoid membrane that reveals nanodomains of colocalized PSII and cytb6f complexes. We suggest that the close proximity between PSII and cytb6f complexes integrates solar energy conversion and electron transfer by fostering short-range diffusion of PQ in the protein-crowded thylakoid membrane, thereby optimizing photosynthetic efficiency.
Collapse
Affiliation(s)
- Matthew P Johnson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - John D Olsen
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| |
Collapse
|
19
|
Patel R, Vasilev C, Beck D, Monteferrante CG, van Dijl JM, Hunter CN, Smith C, Robinson C. A mutation leading to super-assembly of twin-arginine translocase (Tat) protein complexes. Biochim Biophys Acta 2014; 1843:1978-86. [PMID: 24875903 DOI: 10.1016/j.bbamcr.2014.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 05/16/2014] [Accepted: 05/19/2014] [Indexed: 10/25/2022]
Abstract
The Tat system transports folded proteins across the bacterial plasma membrane. The mechanism is believed to involve coalescence of a TatC-containing unit with a separate TatA complex, but the full translocation complex has never been visualised and the assembly process is poorly defined. We report the analysis of the Bacillus subtilis TatAyCy system, which occurs as separate TatAyCy and TatAy complexes at steady state, using single-particle electron microscopy (EM) and advanced atomic force microscopy (AFM) approaches. We show that a P2A mutation in the TatAy subunit leads to apparent super-assembly of Tat complexes. Purification of TatCy-containing complexes leads to a large increase in the TatA:TatC ratio, suggesting that TatAy(P2A) complexes may have attached to the TatAyCy complex. EM and AFM analyses show that the wild-type TatAyCy complex purifies as roughly spherical complexes of 9-16nm diameter, whereas the P2A mutation leads to accumulation of large (up to 500nm long) fibrils that are chains of numerous complexes. Time lapsed AFM imaging, recorded on fibrils under liquid, shows that they adopt a variety of tightly curved conformations, with radii of curvature of 10-12nm comparable to the size of single TatAy(P2A) complexes. The combined data indicate that the mutation leads to super-assembly of TatAy(P2A) complexes and we propose that an individual TatAy(P2A) complex assembles initially with a TatAy(P2A)Cy complex, after which further TatAy(P2A) complexes attach to each other. The data further suggest that the N-terminal extracytoplasmic domain of TatAy plays an essential role in Tat complex interactions.
Collapse
Affiliation(s)
- Roshani Patel
- School of Life Sciences, Gibbet Hill Campus, The University of Warwick, Coventry CV4 7AL, UK
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Daniel Beck
- School of Life Sciences, Gibbet Hill Campus, The University of Warwick, Coventry CV4 7AL, UK
| | - Carmine G Monteferrante
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jan Maarten van Dijl
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Corinne Smith
- School of Life Sciences, Gibbet Hill Campus, The University of Warwick, Coventry CV4 7AL, UK
| | - Colin Robinson
- Centre for Molecular Processing, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK.
| |
Collapse
|
20
|
Vasilev C, Brindley AA, Olsen JD, Saer RG, Beatty JT, Hunter CN. Nano-mechanical mapping of the interactions between surface-bound RC-LH1-PufX core complexes and cytochrome c 2 attached to an AFM probe. Photosynth Res 2014; 120:169-180. [PMID: 23539360 PMCID: PMC4104003 DOI: 10.1007/s11120-013-9812-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 03/11/2013] [Indexed: 05/29/2023]
Abstract
Electron transfer pathways in photosynthesis involve interactions between membrane-bound complexes such as reaction centres with an extrinsic partner. In this study, the biological specificity of electron transfer between the reaction centre-light-harvesting 1-PufX complex and its extrinsic electron donor, cytochrome c 2, formed the basis for mapping the location of surface-attached RC-LH1-PufX complexes using atomic force microscopy (AFM). This nano-mechanical mapping method used an AFM probe functionalised with cyt c 2 molecules to quantify the interaction forces involved, at the single-molecule level under native conditions. With surface-bound RC-His12-LH1-PufX complexes in the photo-oxidised state, the mean interaction force with cyt c 2 is approximately 480 pN with an interaction frequency of around 66 %. The latter value lowered 5.5-fold when chemically reduced RC-His12-LH1-PufX complexes are imaged in the dark to abolish electron transfer from cyt c 2 to the RC. The correspondence between topographic and adhesion images recorded over the same area of the sample shows that affinity-based AFM methods are a useful tool when topology alone is insufficient for spatially locating proteins at the surface of photosynthetic membranes.
Collapse
Affiliation(s)
- Cvetelin Vasilev
- />Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN UK
| | - Amanda A. Brindley
- />Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN UK
| | - John D. Olsen
- />Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN UK
| | - Rafael G. Saer
- />Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3 Canada
| | - J. T. Beatty
- />Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3 Canada
| | - C. N. Hunter
- />Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN UK
| |
Collapse
|
21
|
Ul-Haq E, Patole S, Moxey M, Amstad E, Vasilev C, Hunter CN, Leggett GJ, Spencer ND, Williams NH. Photocatalytic nanolithography of self-assembled monolayers and proteins. ACS Nano 2013; 7:7610-8. [PMID: 23971891 PMCID: PMC4327559 DOI: 10.1021/nn402063b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 08/23/2013] [Indexed: 05/23/2023]
Abstract
Self-assembled monolayers of alkylthiolates on gold and alkylsilanes on silicon dioxide have been patterned photocatalytically on sub-100 nm length-scales using both apertured near-field and apertureless methods. Apertured lithography was carried out by means of an argon ion laser (364 nm) coupled to cantilever-type near-field probes with a thin film of titania deposited over the aperture. Apertureless lithography was carried out with a helium-cadmium laser (325 nm) to excite titanium-coated, contact-mode atomic force microscope (AFM) probes. This latter approach is readily implementable on any commercial AFM system. Photodegradation occurred in both cases through the localized photocatalytic degradation of the monolayer. For alkanethiols, degradation of one thiol exposed the bare substrate, enabling refunctionalization of the bare gold by a second, contrasting thiol. For alkylsilanes, degradation of the adsorbate molecule provided a facile means for protein patterning. Lines were written in a protein-resistant film formed by the adsorption of oligo(ethylene glycol)-functionalized trichlorosilanes on glass, leading to the formation of sub-100 nm adhesive, aldehyde-functionalized regions. These were derivatized with aminobutylnitrilotriacetic acid, and complexed with Ni(2+), enabling the binding of histidine-labeled green fluorescent protein, which yielded bright fluorescence from 70-nm-wide lines that could be imaged clearly in a confocal microscope.
Collapse
Affiliation(s)
- Ehtsham Ul-Haq
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| | - Samson Patole
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Mark Moxey
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| | - Esther Amstad
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Cvetelin Vasilev
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
| | - C. Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
| | - Graham J. Leggett
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| | - Nicholas D. Spencer
- Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Nicholas H. Williams
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, United Kingdom
| |
Collapse
|
22
|
Wang L, Vasilev C, Canniffe DP, Wilson LR, Hunter CN, Cadby AJ. Highly confined surface imaging by solid immersion total internal reflection fluorescence microscopy. Opt Express 2012; 20:3311-3324. [PMID: 22330569 DOI: 10.1364/oe.20.003311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report the use of a high-refractive-index aplanatic solid immersion lens (ASIL) in total internal reflection fluorescence (TIRF) microscopy. This new solid immersion total internal reflection fluorescence (SITIRF) microscopy allows highly confined surface imaging with a significantly reduced imaging depth compared with conventional TIRF microscopy. We explore the application of a high refractive index, low optical dispersion material zirconium dioxide in the SITIRF microscope and also introduce a novel system design which enables the SITIRF microscope to work either in the epi-fluorescence or TIRF modes with variable illumination angles. We use both synthetic and biological samples to demonstrate that the imaging depth in the SITIRF microscope can be confined to a few tens of nanometers. SITIRF microscopy has the advantages of performing highly selective imaging and high-resolution high-contrast imaging. Potential applications in biological imaging and future developments of SITIRF microscopy are proposed.
Collapse
Affiliation(s)
- Lin Wang
- Department of Physics and Astronomy, The University of Sheffield, The Hicks Building, Hounsfield Road, Sheffield, S3 7RH, UK.
| | | | | | | | | | | |
Collapse
|
23
|
Ng IW, Adams PG, Mothersole DJ, Vasilev C, Martin EC, Lang HP, Tucker JD, Neil Hunter C. Carotenoids are essential for normal levels of dimerisation of the RC-LH1-PufX core complex of Rhodobacter sphaeroides: characterisation of R-26 as a crtB (phytoene synthase) mutant. Biochim Biophys Acta 2011; 1807:1056-63. [PMID: 21651888 DOI: 10.1016/j.bbabio.2011.05.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 05/18/2011] [Accepted: 05/23/2011] [Indexed: 02/02/2023]
Abstract
Carotenoids play important roles in photosynthesis where they are involved in light-harvesting, in photo-protection and in the assembly and structural stability of light-harvesting and reaction centre complexes. In order to examine the effects of carotenoids on the oligomeric state of the reaction centre-light-harvesting 1 -PufX (RC-LH1-PufX) core complex of Rhodobacter sphaeroides two carotenoid-less mutants, TC70 and R-26, were studied. Detergent fractionation showed that in the absence of carotenoids LH2 complexes do not assemble, as expected, but also that core complexes are predominantly found as monomers, although levels of the PufX polypeptide appeared to be unaffected. Analysis of R-26 membranes by electron microscopy and atomic force microscopy reveals arrays of hexagonally packed monomeric RC-LH1-PufX complexes. Transfer of the crtB gene encoding phytoene synthase to TC70 and R-26 restores the normal synthesis of carotenoids demonstrating that the R-26 mutant of Rba. sphaeroides harbours a mutation in crtB, among its other defects. The transconjugant TC70 and R-26 strains containing crtB had regained their ability to assemble wild-type levels of dimeric RC-LH1-PufX core complexes and normal energy transfer pathways were restored, demonstrating that carotenoids are essential for the normal assembly and function of both the LH2 and RC-LH1-PufX complexes in this bacterial photosystem.
Collapse
Affiliation(s)
- Irene W Ng
- Department of Molecular Biology and Biochemistry, University of Sheffield S10 2TN, UK
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Kailas L, Vasilev C, Audinot JN, Migeon HN, Hobbs JK. A Real-Time Study of Homogeneous Nucleation, Growth, and Phase Transformations in Nanodroplets of Low Molecular Weight Isotactic Polypropylene Using AFM. Macromolecules 2007. [DOI: 10.1021/ma070861t] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lekshmi Kailas
- Departments of “Physics & Astronomy” and Chemistry, University of Sheffield, Sheffield S3 7RH, UK, and Département Science et Analyse des Matériaux CRPGL, 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | - Cvetelin Vasilev
- Departments of “Physics & Astronomy” and Chemistry, University of Sheffield, Sheffield S3 7RH, UK, and Département Science et Analyse des Matériaux CRPGL, 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | - Jean-Nicolas Audinot
- Departments of “Physics & Astronomy” and Chemistry, University of Sheffield, Sheffield S3 7RH, UK, and Département Science et Analyse des Matériaux CRPGL, 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | - Henri-Noël Migeon
- Departments of “Physics & Astronomy” and Chemistry, University of Sheffield, Sheffield S3 7RH, UK, and Département Science et Analyse des Matériaux CRPGL, 41 rue du Brill, L-4422 Belvaux, Luxembourg
| | - Jamie K. Hobbs
- Departments of “Physics & Astronomy” and Chemistry, University of Sheffield, Sheffield S3 7RH, UK, and Département Science et Analyse des Matériaux CRPGL, 41 rue du Brill, L-4422 Belvaux, Luxembourg
| |
Collapse
|
25
|
|
26
|
Abstract
The VideoAFM provides a 1000 fold increase in image rate compared to conventional atomic force microscopes, giving nanometre resolution images of surfaces at a rate of 15 frames s(-1), which is approximately 1 million pixels s(-1). Images of high stiffness surfaces such as calibration grids are provided for the first time, and allow for a more rigorous examination of the meaning of the data obtained with the VideoAFM. Instrumental changes that could provide true topographic images are discussed. The advantages of a high speed scanning technique that is integrated within a conventional AFM are outlined. Particular emphasis is given to the capability to 'tile' images, and hence rapidly map large areas with nanometre resolution. It is found that the inherent increase in stability that comes from a high frame rate leads to the possibility of manually manipulating the sample while maintaining a sharp image, allowing real-time user interaction with the AFM. The possible application of the VideoAFM approach for the very rapid analysis of surface properties and, ultimately, surface chemistry is discussed and some possible routes are given.
Collapse
Affiliation(s)
- Jamie K Hobbs
- Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK.
| | | | | |
Collapse
|
27
|
|
28
|
|
29
|
Vasilev C, Heinzelmann H, Reiter G. Controlled melting of individual, nano-meter-sized, polymer crystals confined in a block copolymer mesostructure. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/polb.20002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
30
|
Vasilev C, Lichtenberg J. [New type of electrodes for defibrillation of the heart (author's transl)]. Sb Lek 1979; 81:113-6. [PMID: 441674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
31
|
Musil J, Vasilev C. [On the problems concerning the efficiency of balloon contrapulsation on a model line (author's transl)]. Cas Lek Cesk 1976; 115:745-51. [PMID: 949720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|