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Luisa
Sauthof
,
Michal
Szczepek
,
Andrea
Schmidt
,
Asmit
Bhowmick
,
Medhanjali
Dasgupta
,
Megan J.
Mackintosh
,
Sheraz
Gul
,
Franklin D.
Fuller
,
Ruchira
Chatterjee
,
Iris D.
Young
,
Norbert
Michael
,
Nicolas Andreas
Heyder
,
Brian
Bauer
,
Anja
Koch
,
Isabel
Bogacz
,
In-Sik
Kim
,
Philipp S.
Simon
,
Agata
Butryn
,
Pierre
Aller
,
Volha U.
Chukhutsina
,
James M.
Baxter
,
Christopher D. M.
Hutchison
,
Dorothee
Liebschner
,
Billy
Poon
,
Nicholas K.
Sauter
,
Mitchell D.
Miller
,
George N.
Phillips
,
Roberto
Alonso-Mori
,
Mark S.
Hunter
,
Alexander
Batyuk
,
Shigeki
Owada
,
Kensuke
Tono
,
Rie
Tanaka
,
Jasper J.
Van Thor
,
Norbert
Krauß
,
Tilman
Lamparter
,
Aaron S.
Brewster
,
Igor
Schapiro
,
Allen M.
Orville
,
Vittal K.
Yachandra
,
Junko
Yano
,
Peter
Hildebrandt
,
Jan F.
Kern
,
Patrick
Scheerer
Open Access
Abstract: The photoreaction and commensurate structural changes of a chromophore within biological photoreceptors elicit conformational transitions of the protein promoting the switch between deactivated and activated states. We investigated how this coupling is achieved in a bacterial phytochrome variant, Agp2-PAiRFP2. Contrary to classical protein crystallography, which only allows probing (cryo-trapped) stable states, we have used time-resolved serial femtosecond x-ray crystallography (tr-SFX) and pump-probe techniques with various illumination and delay times with respect to photoexcitation of the parent Pfr state. Thus, structural data for seven time frames were sorted into groups of molecular events along the reaction coordinate. They range from chromophore isomerization to the formation of Meta-F, the intermediate that precedes the functional relevant secondary structure transition of the tongue. Structural data for the early events were used to calculate the photoisomerization pathway to complement the experimental data. Late events allow identifying the molecular switch that is linked to the intramolecular proton transfer as a prerequisite for the following structural transitions.
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May 2025
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NONE-No attached Diamond beamline
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Open Access
Abstract: We have developed sample-efficient delivery and reaction initiation strategies that use room temperature microcrystal slurries and serial crystallography methods for time-resolved studies [1-3]. However, interpreting electron density maps from reaction cycle intermediates can be challenging when mixtures of species are present in the data. Therefore, to help reduce ambiguity we and our collaborators have also pioneered strategies to simultaneously collect time-resolved serial crystallography (tr- SSX/tr-SFX) diffraction data in the forward direction, and X-ray emission spectroscopy (tr-XES) data at ∼ 90°, using either XFEL (tr-SFX) or synchrotron (tr-SSX) sources. The resulting atomic and electronic structures are fully correlated and have been applied to a range of enzymes [1, 2, 4-8]. For instance, isopenicillin N synthase (IPNS) uses nonheme iron to catalyse the O2- dependent conversion of its tripeptide substrate delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine (ACV) into isopenicillin N (IPN, the precursor of all penicillin/cephalosporin beta-lactam antibiotics). The unique four electron oxidation reaction leading to the beta-lactam bicyclic ring proceeds via two high-valent iron species, an Fe(III)-superoxo and a high-spin Fe(IV)=O oxyferryl species. These enable two sequential C-H bond cleavage steps that each exhibit large kinetic isotope effects (KIE). Our recent tr- SFX and tr-XES studies have characterised the Fe(III)-superoxo species and revealed unexpected, correlated motions throughout the whole protein caused by O2 binding [4].
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Mar 2025
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Abstract: Dynamic structural biology enables studying biological events at the atomic scale from 10’s of femtoseconds to a few seconds duration. With the advent of X-ray Free Electron Lasers (XFELs) and 4th generation synchrotrons, serial crystallography is becoming a major player for time-resolved experiments in structural biology. Despite significant progress, challenges such as obtaining sufficient amounts of protein to produce homogeneous microcrystal slurry, remain. Given this, it has been paramount to develop instrumentation that reduces the amount of microcrystal slurry required for experiments. Tape-drive systems use a conveyor belt made of X-ray transparent material as a motorized solid-support to steer deposited microcrystals into the beam. For efficient sample consumption on-demand ejectors can be synchronized with the X-ray pulses to expose crystals contained in droplets deposited on the tape. Reactions in the crystals can be triggered via various strategies, including pump-probe, substrate/ligand mixing, or gas incubation in the space between droplet ejection and X-ray illumination. Another challenge in time-resolved serial crystallography is interpreting the resulting electron density maps. This is especially difficult for metalloproteins where the active site metal is intimately involved in catalysis and often proceeds through multiple oxidation states during enzymatic catalysis. The unrestricted space around tape-drive systems can be used to accommodate complementary spectroscopic equipment. Here, we highlight tape-drive sample delivery systems for complementary and simultaneous X-ray diffraction (XRD) and X-ray emission spectroscopy (XES) measurements. We describe how the combination of both XRD and XES is a powerful tool for time-resolved experiments at XFELs and synchrotrons.
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Oct 2024
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Romie C.
Nguyen
,
Ian
Davis
,
Medhanjali
Dasgupta
,
Yifan
Wang
,
Philipp S.
Simon
,
Agata
Butryn
,
Hiroki
Makita
,
Isabel
Bogacz
,
Kednerlin
Dornevil
,
Pierre
Aller
,
Asmit
Bhowmick
,
Ruchira
Chatterjee
,
In-Sik
Kim
,
Tiankun
Zhou
,
Derek
Mendez
,
Daniel W.
Paley
,
Franklin
Fuller
,
Roberto
Alonso Mori
,
Alexander
Batyuk
,
Nicholas K.
Sauter
,
Aaron S.
Brewster
,
Allen M.
Orville
,
Vittal K.
Yachandra
,
Junko
Yano
,
Jan F.
Kern
,
Aimin
Liu
Abstract: The P450 enzyme CYP121 from Mycobacterium tuberculosis catalyzes a carbon–carbon (C–C) bond coupling cyclization of the dityrosine substrate containing a diketopiperazine ring, cyclo(l-tyrosine-l-tyrosine) (cYY). An unusual high-spin (S = 5/2) ferric intermediate maximizes its population in less than 5 ms in the rapid freeze-quenching study of CYP121 during the shunt reaction with peracetic acid or hydrogen peroxide in acetic acid solution. We show that this intermediate can also be observed in the crystalline state by EPR spectroscopy. By developing an on-demand-rapid-mixing method for time-resolved serial femtosecond crystallography with X-ray free-electron laser (tr-SFX-XFEL) technology covering the millisecond time domain and without freezing, we structurally monitored the reaction in situ at room temperature. After a 200 ms peracetic acid reaction with the cocrystallized enzyme–substrate microcrystal slurry, a ferric-hydroperoxo intermediate is observed, and its structure is determined at 1.85 Å resolution. The structure shows a hydroperoxyl ligand between the heme and the native substrate, cYY. The oxygen atoms of the hydroperoxo are 2.5 and 3.2 Å from the iron ion. The end-on binding ligand adopts a near-side-on geometry and is weakly associated with the iron ion, causing the unusual high-spin state. This compound 0 intermediate, spectroscopically and structurally observed during the catalytic shunt pathway, reveals a unique binding mode that deviates from the end-on compound 0 intermediates in other heme enzymes. The hydroperoxyl ligand is only 2.9 Å from the bound cYY, suggesting an active oxidant role of the intermediate for direct substrate oxidation in the nonhydroxylation C–C bond coupling chemistry.
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Nov 2023
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I24-Microfocus Macromolecular Crystallography
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James
Birch
,
Tristan O. C.
Kwan
,
Peter J.
Judge
,
Danny
Axford
,
Pierre
Aller
,
Agata
Butryn
,
Rosana
Reis
,
Juan F.
Bada Juarez
,
Javier
Vinals
,
Robin L.
Owen
,
Eriko
Nango
,
Rie
Tanaka
,
Kensuke
Tono
,
Yasumasa
Joti
,
Tomoyuki
Tanaka
,
Shigeki
Owada
,
Michihiro
Sugahara
,
So
Iwata
,
Allen M.
Orville
,
Anthony
Watts
,
Isabel
Moraes
Diamond Proposal Number(s):
[19152]
Open Access
Abstract: Serial crystallography has emerged as an important tool for structural studies of integral membrane proteins. The ability to collect data from micrometre-sized weakly diffracting crystals at room temperature with minimal radiation damage has opened many new opportunities in time-resolved studies and drug discovery. However, the production of integral membrane protein microcrystals in lipidic cubic phase at the desired crystal density and quantity is challenging. This paper introduces VIALS (versatile approach to high-density microcrystals in lipidic cubic phase for serial crystallography), a simple, fast and efficient method for preparing hundreds of microlitres of high-density microcrystals suitable for serial X-ray diffraction experiments at both synchrotron and free-electron laser sources. The method is also of great benefit for rational structure-based drug design as it facilitates in situ crystal soaking and rapid determination of many co-crystal structures. Using the VIALS approach, room-temperature structures are reported of (i) the archaerhodopsin-3 protein in its dark-adapted state and 110 ns photocycle intermediate, determined to 2.2 and 1.7 Å, respectively, and (ii) the human A2A adenosine receptor in complex with two different ligands determined to a resolution of 3.5 Å.
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Oct 2023
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Hugo
Lebrette
,
Vivek
Srinivas
,
Juliane
John
,
Oskar
Aurelius
,
Rohit
Kumar
,
Daniel
Lundin
,
Aaron S.
Brewster
,
Asmit
Bhowmick
,
Abhishek
Sirohiwal
,
In-Sik
Kim
,
Sheraz
Gul
,
Cindy
Pham
,
Kyle D.
Sutherlin
,
Philipp
Simon
,
Agata
Butryn
,
Pierre
Aller
,
Allen M.
Orville
,
Franklin D.
Fuller
,
Roberto
Alonso-Mori
,
Alexander
Batyuk
,
Nicholas K.
Sauter
,
Vittal K.
Yachandra
,
Junko
Yano
,
Ville R. I.
Kaila
,
Britt-Marie
Sjöberg
,
Jan
Kern
,
Katarina
Roos
,
Martin
Högbom
Abstract: Aerobic ribonucleotide reductases (RNRs) initiate synthesis of DNA building blocks by generating a free radical within the R2 subunit; the radical is subsequently shuttled to the catalytic R1 subunit through proton-coupled electron transfer (PCET). We present a high-resolution room temperature structure of the class Ie R2 protein radical captured by x-ray free electron laser serial femtosecond crystallography. The structure reveals conformational reorganization to shield the radical and connect it to the translocation path, with structural changes propagating to the surface where the protein interacts with the catalytic R1 subunit. Restructuring of the hydrogen bond network, including a notably short O–O interaction of 2.41 angstroms, likely tunes and gates the radical during PCET. These structural results help explain radical handling and mobilization in RNR and have general implications for radical transfer in proteins.
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Oct 2023
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I24-Microfocus Macromolecular Crystallography
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Open Access
Abstract: Proof of concept of serial crystallography is carried out through the translation of samples delivered by tractor beam levitation. This is achieved using arrays of low powered transducers, focused to produce acoustic traps. Contrary to traditional Langevin Horn levitators, power requirement remains in the region of 10W, limiting the acoustic pressure on the levitated samples and hence the risk of damage to them. Automation is achieved by controlling the phase of the transducers. The traps and associated samples steadily translate with the controlled acoustic field. A translation speed of 2.8mms−1 between the nodal distance of the traps is achieved. This results in sequential delivery of sample containing droplets performed with 1.5s between each delivery. The results demonstrate the ability to capture automated measurements of diffraction from lysozyme micro-crystals. Our study points in the direction of an automated, acoustic levitation system for time-resolved crystallography.
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Dec 2022
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I24-Microfocus Macromolecular Crystallography
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James
Baxter
,
Christopher D. M.
Hutchison
,
Karim
Maghlaoui
,
Violeta
Cordon-Preciado
,
R. Marc L.
Morgan
,
Pierre
Aller
,
Agata
Butryn
,
Danny
Axford
,
Sam
Horrell
,
Robin L.
Owen
,
Selina L. S.
Storm
,
Nicholas E.
Devenish
,
Jasper J.
Van Thor
Diamond Proposal Number(s):
[17221]
Open Access
Abstract: The chromophores of reversibly switchable fluorescent proteins (rsFPs) undergo photoisomerization of both the trans and cis forms. Concurrent with cis/trans photoisomerisation, rsFPs typically become protonated on the phenolic oxygen resulting in a blue shift of the absorption. A synthetic rsFP referred to as rsEospa, derived from EosFP family, displays the same spectroscopic behavior as the GFP-like rsFP Dronpa at pH 8.4 and involves the photoconversion between nonfluorescent neutral and fluorescent anionic chromophore states. Millisecond time-resolved synchrotron serial crystallography of rsEospa at pH 8.4 shows that photoisomerization is accompanied by rearrangements of the same three residues as seen in Dronpa. However, at pH 5.5 we observe that the OFF state is identified as the cationic chromophore with additional protonation of the imidazolinone nitrogen which is concurrent with a newly formed hydrogen bond with the Glu212 carboxylate side chain. FTIR spectroscopy resolves the characteristic up-shifted carbonyl stretching frequency at 1713 cm–1 for the cationic species. Electronic spectroscopy furthermore distinguishes the cationic absorption band at 397 nm from the neutral species at pH 8.4 seen at 387 nm. The observation of photoisomerization of the cationic chromophore state demonstrates the conical intersection for the electronic configuration, where previously fluorescence was proposed to be the main decay route for states containing imidazolinone nitrogen protonation. We present the full time-resolved room-temperature X-ray crystallographic, FTIR, and UV/vis assignment and photoconversion modeling of rsEospa.
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Nov 2022
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Juliane
John
,
Oskar
Aurelius
,
Vivek
Srinivas
,
Patricia
Saura
,
In-Sik
Kim
,
Asmit
Bhowmick
,
Philipp S.
Simon
,
Medhanjali
Dasgupta
,
Cindy
Pham
,
Sheraz
Gul
,
Kyle D.
Sutherlin
,
Pierre
Aller
,
Agata
Butryn
,
Allen M.
Orville
,
Mun Hon
Cheah
,
Shigeki
Owada
,
Kensuke
Tono
,
Franklin D
Fuller
,
Alexander
Batyuk
,
Aaron S.
Brewster
,
Nicholas K.
Sauter
,
Vittal K
Yachandra
,
Junko
Yano
,
Ville R. I.
Kaila
,
Jan
Kern
,
Hugo
Lebrette
,
Martin
Högbom
Open Access
Abstract: Redox reactions are central to biochemistry and are both controlled by and induce protein structural changes. Here, we describe structural rearrangements and crosstalk within the Bacillus cereus ribonucleotide reductase R2b–NrdI complex, a di-metal carboxylate-flavoprotein system, as part of the mechanism generating the essential catalytic free radical of the enzyme. Femtosecond crystallography at an X-ray free electron laser was utilized to obtain structures at room temperature in defined redox states without suffering photoreduction. Together with density functional theory calculations, we show that the flavin is under steric strain in the R2b–NrdI protein complex, likely tuning its redox properties to promote superoxide generation. Moreover, a binding site in close vicinity to the expected flavin O2 interaction site is observed to be controlled by the redox state of the flavin and linked to the channel proposed to funnel the produced superoxide species from NrdI to the di-manganese site in protein R2b. These specific features are coupled to further structural changes around the R2b–NrdI interaction surface. The mechanistic implications for the control of reactive oxygen species and radical generation in protein R2b are discussed.
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Sep 2022
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I24-Microfocus Macromolecular Crystallography
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Richard J.
Gildea
,
James
Beilsten-Edmands
,
Danny
Axford
,
Sam
Horrell
,
Pierre
Aller
,
James
Sandy
,
Juan
Sanchez-Weatherby
,
C. David
Owen
,
Petra
Lukacik
,
Claire
Strain-Damerell
,
Robin L.
Owen
,
Martin A.
Walsh
,
Graeme
Winter
Diamond Proposal Number(s):
[26986, 27088]
Open Access
Abstract: In macromolecular crystallography, radiation damage limits the amount of data that can be collected from a single crystal. It is often necessary to merge data sets from multiple crystals; for example, small-wedge data collections from micro-crystals, in situ room-temperature data collections and data collection from membrane proteins in lipidic mesophases. Whilst the indexing and integration of individual data sets may be relatively straightforward with existing software, merging multiple data sets from small wedges presents new challenges. The identification of a consensus symmetry can be problematic, particularly in the presence of a potential indexing ambiguity. Furthermore, the presence of non-isomorphous or poor-quality data sets may reduce the overall quality of the final merged data set. To facilitate and help to optimize the scaling and merging of multiple data sets, a new program, xia2.multiplex, has been developed which takes data sets individually integrated with DIALS and performs symmetry analysis, scaling and merging of multi-crystal data sets. xia2.multiplex also performs analysis of various pathologies that typically affect multi-crystal data sets, including non-isomorphism, radiation damage and preferential orientation. After the description of a number of use cases, the benefit of xia2.multiplex is demonstrated within a wider autoprocessing framework in facilitating a multi-crystal experiment collected as part of in situ room-temperature fragment-screening experiments on the SARS-CoV-2 main protease.
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Jun 2022
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