I24-Microfocus Macromolecular Crystallography
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Rachel
Bolton
,
Moritz M.
Machelett
,
Jack
Stubbs
,
Danny
Axford
,
Nicolas
Caramello
,
Lucrezia
Catapano
,
Martin
Maly
,
Matthew J.
Rodrigues
,
Charlotte
Cordery
,
Graham J.
Tizzard
,
Fraser
Macmillan
,
Sylvain
Engilberge
,
David
Von Stetten
,
Takehiko
Tosha
,
Hiroshi
Sugimoto
,
Jonathan A. R.
Worrall
,
Jeremy S.
Webb
,
Mike
Zubkov
,
Simon
Coles
,
Eric
Mathieu
,
Roberto A.
Steiner
,
Garib
Murshudov
,
Tobias E.
Schrader
,
Allen M.
Orville
,
Antoine
Royant
,
Gwyndaf
Evans
,
Michael A.
Hough
,
Robin L.
Owen
,
Ivo
Tews
Diamond Proposal Number(s):
[15722, 14493, 23570]
Open Access
Abstract: The marine cyanobacterium Prochlorococcus is a main contributor to global photosynthesis, whilst being limited by iron availability. Cyanobacterial genomes generally encode two different types of FutA iron-binding proteins: periplasmic FutA2 ABC transporter subunits bind Fe(III), while cytosolic FutA1 binds Fe(II). Owing to their small size and their economized genome Prochlorococcus ecotypes typically possess a single futA gene. How the encoded FutA protein might bind different Fe oxidation states was previously unknown. Here, we use structural biology techniques at room temperature to probe the dynamic behavior of FutA. Neutron diffraction confirmed four negatively charged tyrosinates, that together with a neutral water molecule coordinate iron in trigonal bipyramidal geometry. Positioning of the positively charged Arg103 side chain in the second coordination shell yields an overall charge-neutral Fe(III) binding state in structures determined by neutron diffraction and serial femtosecond crystallography. Conventional rotation X-ray crystallography using a home source revealed X-ray-induced photoreduction of the iron center with observation of the Fe(II) binding state; here, an additional positioning of the Arg203 side chain in the second coordination shell maintained an overall charge neutral Fe(II) binding site. Dose series using serial synchrotron crystallography and an XFEL X-ray pump–probe approach capture the transition between Fe(III) and Fe(II) states, revealing how Arg203 operates as a switch to accommodate the different iron oxidation states. This switching ability of the Prochlorococcus FutA protein may reflect ecological adaptation by genome streamlining and loss of specialized FutA proteins.
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Mar 2024
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I04-Macromolecular Crystallography
VMXi-Versatile Macromolecular Crystallography in situ
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Halina
Mikolajek
,
Juan
Sanchez-Weatherby
,
James
Sandy
,
Richard J.
Gildea
,
Ivan
Campeotto
,
Harish
Cheruvara
,
John D.
Clarke
,
Toshana
Foster
,
Sotaro
Fujii
,
Ian T.
Paulsen
,
Bhumika S.
Shah
,
Michael A.
Hough
Open Access
Abstract: The utility of X-ray crystal structures determined under ambient-temperature conditions is becoming increasingly recognized. Such experiments can allow protein dynamics to be characterized and are particularly well suited to challenging protein targets that may form fragile crystals that are difficult to cryo-cool. Room-temperature data collection also enables time-resolved experiments. In contrast to the high-throughput highly automated pipelines for determination of structures at cryogenic temperatures widely available at synchrotron beamlines, room-temperature methodology is less mature. Here, the current status of the fully automated ambient-temperature beamline VMXi at Diamond Light Source is described, and a highly efficient pipeline from protein sample to final multi-crystal data analysis and structure determination is shown. The capability of the pipeline is illustrated using a range of user case studies representing different challenges, and from high and lower symmetry space groups and varied crystal sizes. It is also demonstrated that very rapid structure determination from crystals in situ within crystallization plates is now routine with minimal user intervention.
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Jul 2023
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I23-Long wavelength MX
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Alisia
Fadini
,
Christopher D. M.
Hutchison
,
Dmitry
Morozov
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Jeffrey
Chang
,
Karim
Maghlaoui
,
Samuel
Perrett
,
Fangjia
Luo
,
Jeslyn C. X.
Kho
,
Matthew G.
Romei
,
R. Marc L.
Morgan
,
Christian
Orr
,
Violeta
Cordon-Preciado
,
Takaaki
Fujiwara
,
Nipawan
Nuemket
,
Takehiko
Tosha
,
Rie
Tanaka
,
Shigeki
Owada
,
Kensuke
Tono
,
So
Iwata
,
Steven G.
Boxer
,
Gerrit
Groenhof
,
Eriko
Nango
,
Jasper J.
Van Thor
Diamond Proposal Number(s):
[23620]
Open Access
Abstract: Chromophore cis/trans photoisomerization is a fundamental process in chemistry and in the activation of many photosensitive proteins. A major task is understanding the effect of the protein environment on the efficiency and direction of this reaction compared to what is observed in the gas and solution phases. In this study, we set out to visualize the hula twist (HT) mechanism in a fluorescent protein, which is hypothesized to be the preferred mechanism in a spatially constrained binding pocket. We use a chlorine substituent to break the twofold symmetry of the embedded phenolic group of the chromophore and unambiguously identify the HT primary photoproduct. Through serial femtosecond crystallography, we then track the photoreaction from femtoseconds to the microsecond regime. We observe signals for the photoisomerization of the chromophore as early as 300 fs, obtaining the first experimental structural evidence of the HT mechanism in a protein on its femtosecond-to-picosecond timescale. We are then able to follow how chromophore isomerization and twisting lead to secondary structure rearrangements of the protein β-barrel across the time window of our measurements.
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Jul 2023
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I24-Microfocus Macromolecular Crystallography
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Diamond Proposal Number(s):
[25108, 28583]
Open Access
Abstract: Controlling the reactivity of high-valent Fe(IV)–O catalytic intermediates, Compounds I and II, generated in heme enzymes upon reaction with dioxygen or hydrogen peroxide, is important for function. It has been hypothesized that the presence (wet) or absence (dry) of distal heme pocket water molecules can influence whether Compound I undergoes sequential one-electron additions or a concerted two-electron reduction. To test this hypothesis, we investigate the role of water in the heme distal pocket of a dye-decolorizing peroxidase utilizing a combination of serial femtosecond crystallography and rapid kinetic studies. In a dry distal heme site, Compound I reduction proceeds through a mechanism in which Compound II concentration is low. This reaction shows a strong deuterium isotope effect, indicating that reduction is coupled to proton uptake. The resulting protonated Compound II (Fe(IV)–OH) rapidly reduces to the ferric state, giving the appearance of a two-electron transfer process. In a wet site, reduction of Compound I is faster, has no deuterium effect, and yields highly populated Compound II, which is subsequently reduced to the ferric form. This work provides a definitive experimental test of the hypothesis advanced in the literature that relates sequential or concerted electron transfer to Compound I in wet or dry distal heme sites.
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Oct 2022
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I24-Microfocus Macromolecular Crystallography
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Tadeo
Moreno-Chicano
,
Leiah M.
Carey
,
Danny
Axford
,
John H.
Beale
,
R. Bruce
Doak
,
Helen M. E.
Duyvesteyn
,
Ali
Ebrahim
,
Robert W.
Henning
,
Diana C. F.
Monteiro
,
Dean A.
Myles
,
Shigeki
Owada
,
Darren A.
Sherrell
,
Megan L.
Straw
,
Vukica
Šrajer
,
Hiroshi
Sugimoto
,
Kensuke
Tono
,
Takehiko
Tosha
,
Ivo
Tews
,
Martin
Trebbin
,
Richard W.
Strange
,
Kevin L.
Weiss
,
Jonathan A. R.
Worrall
,
Flora
Meilleur
,
Robin L.
Owen
,
Reza A.
Ghiladi
,
Michael A.
Hough
Diamond Proposal Number(s):
[14493]
Open Access
Abstract: Room-temperature macromolecular crystallography allows protein structures to be determined under close-to-physiological conditions, permits dynamic freedom in protein motions and enables time-resolved studies. In the case of metalloenzymes that are highly sensitive to radiation damage, such room-temperature experiments can present challenges, including increased rates of X-ray reduction of metal centres and site-specific radiation-damage artefacts, as well as in devising appropriate sample-delivery and data-collection methods. It can also be problematic to compare structures measured using different crystal sizes and light sources. In this study, structures of a multifunctional globin, dehaloperoxidase B (DHP-B), obtained using several methods of room-temperature crystallographic structure determination are described and compared. Here, data were measured from large single crystals and multiple microcrystals using neutrons, X-ray free-electron laser pulses, monochromatic synchrotron radiation and polychromatic (Laue) radiation light sources. These approaches span a range of 18 orders of magnitude in measurement time per diffraction pattern and four orders of magnitude in crystal volume. The first room-temperature neutron structures of DHP-B are also presented, allowing the explicit identification of the hydrogen positions. The neutron data proved to be complementary to the serial femtosecond crystallography data, with both methods providing structures free of the effects of X-ray radiation damage when compared with standard cryo-crystallography. Comparison of these room-temperature methods demonstrated the large differences in sample requirements, data-collection time and the potential for radiation damage between them. With regard to the structure and function of DHP-B, despite the results being partly limited by differences in the underlying structures, new information was gained on the protonation states of active-site residues which may guide future studies of DHP-B.
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Sep 2022
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I24-Microfocus Macromolecular Crystallography
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Samuel L.
Rose
,
Seiki
Baba
,
Hideo
Okumura
,
Svetlana V.
Antonyuk
,
Daisuke
Sasaki
,
Tobias M.
Hedison
,
Muralidharan
Shanmugam
,
Derren J.
Heyes
,
Nigel S.
Scrutton
,
Takashi
Kumasaka
,
Takehiko
Tosha
,
Robert R.
Eady
,
Masaki
Yamamoto
,
S. Samar
Hasnain
Open Access
Abstract: Many enzymes utilize redox-coupled centers for performing catalysis where these centers are used to control and regulate the transfer of electrons required for catalysis, whose untimely delivery can lead to a state incapable of binding the substrate, i.e., a dead-end enzyme. Copper nitrite reductases (CuNiRs), which catalyze the reduction of nitrite to nitric oxide (NO), have proven to be a good model system for studying these complex processes including proton-coupled electron transfer (ET) and their orchestration for substrate binding/utilization. Recently, a two-domain CuNiR from a Rhizobia species (Br2DNiR) has been discovered with a substantially lower enzymatic activity where the catalytic type-2 Cu (T2Cu) site is occupied by two water molecules requiring their displacement for the substrate nitrite to bind. Single crystal spectroscopy combined with MSOX (multiple structures from one crystal) for both the as-isolated and nitrite-soaked crystals clearly demonstrate that inter-Cu ET within the coupled T1Cu-T2Cu redox system is heavily gated. Laser-flash photolysis and optical spectroscopy showed rapid ET from photoexcited NADH to the T1Cu center but little or no inter-Cu ET in the absence of nitrite. Furthermore, incomplete reoxidation of the T1Cu site (∼20% electrons transferred) was observed in the presence of nitrite, consistent with a slow formation of NO species in the serial structures of the MSOX movie obtained from the nitrite-soaked crystal, which is likely to be responsible for the lower activity of this CuNiR. Our approach is of direct relevance for studying redox reactions in a wide range of biological systems including metalloproteins that make up at least 30% of all proteins.
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Jul 2022
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Hanna
Kwon
,
Jaswir
Basran
,
Chinar
Pathak
,
Mahdi
Hussain
,
Samuel L.
Freeman
,
Alistair J.
Fielding
,
Anna J.
Bailey
,
Natalia
Stefanou
,
Hazel A.
Sparkes
,
Takehiko
Tosha
,
Keitaro
Yamashita
,
Kunio
Hirata
,
Hironori
Murakami
,
Go
Ueno
,
Hideo
Ago
,
Kensuke
Tono
,
Masaki
Yamamoto
,
Hitomi
Sawai
,
Yoshitsugu
Shiro
,
Hiroshi
Sugimoto
,
Emma
Raven
,
Peter C. E.
Moody
Open Access
Abstract: Oxygen activation in all heme enzymes requires the formation of high oxidation states of iron, usually referred to as ferryl heme. There are two known intermediates: Compound I and Compound II. The nature of the ferryl heme – and whether it is an Fe IV =O or Fe IV ‐OH species – is important for controlling reactivity across groups of heme enzymes. The most recent evidence for Compound I indicates that the ferryl heme is an unprotonated Fe IV =O species. For Compound II, the nature of the ferryl heme is not unambiguously established. Here, we report 1.06 Å and 1.50 Å crystal structures for Compound II intermediates in cytochrome c peroxidase (C c P) and ascorbate peroxidase (APX), collected using the X‐ray free electron laser at SACLA. The structures reveal differences between the two peroxidases. The iron‐oxygen bond length in C c P (1.76 Å) is notably shorter than in APX (1.87 Å). The results indicate that the ferryl species is finely tuned across Compound I and Compound II species in closely related peroxidase enzymes. We propose that this fine‐tuning is linked to the functional need for proton delivery to the heme.
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Apr 2021
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I03-Macromolecular Crystallography
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Samuel L.
Rose
,
Svetlana V.
Antonyuk
,
Daisuke
Sasaki
,
Keitaro
Yamashita
,
Kunio
Hirata
,
Go
Ueno
,
Hideo
Ago
,
Robert R.
Eady
,
Takehiko
Tosha
,
Masaki
Yamamoto
,
S. Samar
Hasnain
Diamond Proposal Number(s):
[15991]
Open Access
Abstract: Copper-containing nitrite reductases (CuNiRs), encoded by nirK gene, are found in all kingdoms of life with only 5% of CuNiR denitrifiers having two or more copies of nirK. Recently, we have identified two copies of nirK genes in several α-proteobacteria of the order Rhizobiales including Bradyrhizobium sp. ORS 375, encoding a four-domain heme-CuNiR and the usual two-domain CuNiR (Br2DNiR). Compared with two of the best-studied two-domain CuNiRs represented by the blue (AxNiR) and green (AcNiR) subclasses, Br2DNiR, a blue CuNiR, shows a substantially lower catalytic efficiency despite a sequence identity of ~70%. Advanced synchrotron radiation and x-ray free-electron laser are used to obtain the most accurate (atomic resolution with unrestrained SHELX refinement) and damage-free (free from radiation-induced chemistry) structures, in as-isolated, substrate-bound, and product-bound states. This combination has shed light on the protonation states of essential catalytic residues, additional reaction intermediates, and how catalytic efficiency is modulated.
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Jan 2021
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Marina
Lucic
,
Dimitri
Svistunenko
,
Michael
Wilson
,
Amanda
Chaplin
,
Bradley
Davy
,
Ali
Ebrahim
,
Danny
Axford
,
Takehiko
Tosha
,
Hiroshi
Sugimoto
,
Shigeki
Owada
,
Florian
Dworkowski
,
Ivo
Tews
,
Robin
Owen
,
Michael
Hough
,
Jonathan A. R.
Worrall
Open Access
Abstract: Obtaining structures of intact redox states of metal centres derived from zero dose X‐ray crystallography can advance our mechanistic understanding of metalloenzymes. In dye‐decolourising heme peroxidases (DyPs), controversy exists regarding the mechanistic role of the distal heme residues, aspartate and arginine, in the heterolysis of peroxide to form the catalytic intermediate compound I (Fe IV =O and a porphyrin cation radical). Using serial femtosecond X‐ray (SFX) crystallography, we have determined the pristine structures of the Fe III and Fe IV =O redox states of a B‐type DyP. These structures reveal a water‐free distal heme site, which together with the presence of an asparagine, infer the use of the distal arginine as a catalytic base. A combination of mutagenesis and kinetic studies corroborate such a role. Our SFX approach thus provides unique insight into how the distal heme site of DyPs can be tuned to select aspartate or arginine for the rate enhancement of peroxide heterolysis.
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Aug 2020
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Krios II-Titan Krios II at Diamond
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Diamond Proposal Number(s):
[19832]
Open Access
Abstract: Neisseria meningitidis is carried by nearly a billion humans, causing developmental impairment and over 100 000 deaths a year. A quinol-dependent nitric oxide reductase (qNOR) plays a critical role in the survival of the bacterium in the human host. X-ray crystallographic analyses of qNOR, including that from N. meningitidis (NmqNOR) reported here at 3.15 Å resolution, show monomeric assemblies, despite the more active dimeric sample being used for crystallization. Cryo-electron microscopic analysis of the same chromatographic fraction of NmqNOR, however, revealed a dimeric assembly at 3.06 Å resolution. It is shown that zinc (which is used in crystallization) binding near the dimer-stabilizing TMII region contributes to the disruption of the dimer. A similar destabilization is observed in the monomeric (∼85 kDa) cryo-EM structure of a mutant (Glu494Ala) qNOR from the opportunistic pathogen Alcaligenes (Achromobacter) xylosoxidans, which primarily migrates as a monomer. The monomer–dimer transition of qNORs seen in the cryo-EM and crystallographic structures has wider implications for structural studies of multimeric membrane proteins. X-ray crystallographic and cryo-EM structural analyses have been performed on the same chromatographic fraction of NmqNOR to high resolution. This represents one of the first examples in which the two approaches have been used to reveal a monomeric assembly in crystallo and a dimeric assembly in vitrified cryo-EM grids. A number of factors have been identified that may trigger the destabilization of helices that are necessary to preserve the integrity of the dimer. These include zinc binding near the entry of the putative proton-transfer channel and the preservation of the conformational integrity of the active site. The mutation near the active site results in disruption of the active site, causing an additional destabilization of helices (TMIX and TMX) that flank the proton-transfer channel helices, creating an inert monomeric enzyme.
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May 2020
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