IUCrJPub Date : 2025-09-01DOI: 10.1107/S2052252525006141
Y. Ishii
{"title":"First high-resolution synchrotron X-ray study of icosahedrite, a natural quasicrystal from the Khatyrka meteorite","authors":"Y. Ishii","doi":"10.1107/S2052252525006141","DOIUrl":"10.1107/S2052252525006141","url":null,"abstract":"<div><div>Quasicrystals are long-range-ordered materials with rotational symmetry incompatible with periodicity. Takakura <em>et al.</em> [(2025). <em>IUCrJ</em><strong>12</strong>, 435–443] present a study of a single grain of icosahedrite, the first natural icosahedral quasicrystal, which was found in a meteorite in 2009. Through detailed analysis of the diffraction peaks, they conclude that natural AlCuFe is an icosahedral quasicrystal superimposed by a phasonic modulation along the fivefold directions, which is similar to that observed in the synthetic quasicrystal. Based on knowledge of the synthesis and phase stability of icosahedral AlCuFe, they discuss the formation of icosahedrite in the meteorite.</div></div>","PeriodicalId":14775,"journal":{"name":"IUCrJ","volume":"12 5","pages":"Pages 511-512"},"PeriodicalIF":3.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144690289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IUCrJPub Date : 2025-09-01DOI: 10.1107/S2052252525005810
Yalan Wei , Shifang Li , Xizhi Shi , Chaoyu He
{"title":"Low-energy tetrahedral networks for carbon and silicon from (2+1)-regular bipartite-like graphs","authors":"Yalan Wei , Shifang Li , Xizhi Shi , Chaoyu He","doi":"10.1107/S2052252525005810","DOIUrl":"10.1107/S2052252525005810","url":null,"abstract":"<div><div>This study identifies carbon crystal structures as 4-degree quotient graphs and proposes a novel approach for generating 3D 4-coordinate networks using 2D (2+1)-regular bipartite-like graphs. Through a random group and graph theory (RG2) method, we discover 509 new structures, including two low-energy phases (<em>Pbam</em>48 and <em>Pbam</em>40) that exhibit exceptional stability and potential applications as superhard carbon and quasi-direct band gap silicon materials in mechanical processing and solar photovoltaic technologies.</div></div><div><div>Post-graphite in cold-compression [Mao <em>et al.</em> (2003). <em>Science</em><strong>302</strong>, 425–427] has attracted widespread research interest in condensed matter physics. Subsequently, many low-energy carbon phases, such as M-carbon, W-carbon and Z-carbon, have been proposed as structural candidates. Based on graph theory, we found that these 4-coordinated post-graphite candidates can not only be decomposed into 3-regular graphitic graphs but also yield (2+1)-regular graphs in a non-graphitic manner from different decomposition directions. This inspires a general idea of generating 3D 4-coordinate networks based on 2D (2+1)-regular bipartite-like graphs, which can be efficiently generated by a random method combined with group and graph theory (RG2). Associated with such a general graph-based method, a large number of 4-coordinate networks have been discovered and investigated by first-principles calculations as potential carbon/silicon phases. Most are confirmed as low-energy carbon/silicon phases and identified as direct or quasi-direct band gap semiconductors. Two complex configurations, <em>Pbam</em>48 and <em>Pbam</em>40, show energetic stabilities exceeding or comparable to the previously proposed <em>Pbam</em>24. They are further confirmed to be dynamically and mechanically stable phases as carbon/silicon. As carbon phases, <em>Pbam</em>48 and <em>Pbam</em>40 are superhard insulators with quasi-direct band gaps of 5.622 and 5.890 eV, and hardness values of 85.352 and 85.558 GPa, respectively. Their X-ray diffraction (XRD) results can largely explain the experimental XRD patterns of cold-compressed graphite. As silicon allotropes, <em>Pbam</em>48 and <em>Pbam</em>40 have quasi-direct band gaps of 1.386 and 1.451 eV, respectively, making them potential solar cell absorber materials.</div></div>","PeriodicalId":14775,"journal":{"name":"IUCrJ","volume":"12 5","pages":"Pages 523-530"},"PeriodicalIF":3.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144731049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IUCrJPub Date : 2025-09-01DOI: 10.1107/S2052252525006062
Tomoki Imura , Yuhei Hosokawa , Kai-Chun Yang , Yuki Ban , Hsuan-Yu Shih , Junpei Yamamoto , Manuel Maestre-Reyna
{"title":"Revisiting the co-crystal structure of a DNA glycosylase with photocaged substrate: a suitable time-resolved crystallography target?","authors":"Tomoki Imura , Yuhei Hosokawa , Kai-Chun Yang , Yuki Ban , Hsuan-Yu Shih , Junpei Yamamoto , Manuel Maestre-Reyna","doi":"10.1107/S2052252525006062","DOIUrl":"10.1107/S2052252525006062","url":null,"abstract":"<div><div>Engineered <em>in crystallo</em> photosensitivity in a DNA-repair enzyme is carefully assessed for its suitability as a target for time-resolved crystallographic studies.</div></div><div><div>Co-crystal structures of a base-excision DNA-repair enzyme (human 8-oxoguanine DNA glycosylase; hOgg1) in complex with a photocaged 8-oxoguanine DNA lesion were determined before and after uncaging via illumination at 2.81 and 2.48 Å resolution, respectively. The structures were carefully reassessed to rapidly expand the target repertoire of light-triggered time-resolved macromolecular crystallography. Late-intermediate cryo-trapping after uncaging revealed the partial accommodation of 8-oxoguanine in the active site with 68% occupancy, which did not induce full active-site adaptation to the catalytic state. Crystal illumination led to a light-dependent loss of diffraction power, likely due to crystal-packing collapse during the very late reaction stages. This work therefore not only demonstrates that hOgg1 is well suited for time-resolved crystallography, but also that such analysis is necessary to determine further steps in its reaction.</div></div>","PeriodicalId":14775,"journal":{"name":"IUCrJ","volume":"12 5","pages":"Pages 515-522"},"PeriodicalIF":3.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144626391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IUCrJPub Date : 2025-09-01DOI: 10.1107/S2052252525005573
Jack Stephens , Ramesh Rijal , Daniel Sier , Nicholas T. T. Tran , Jonathan W. Dean , Paul Di Pasquale , Tony Kirk , Minh Dao , Chanh Q. Tran , Shusaku Hayama , Sofia Diaz-Moreno , Christopher T. Chantler
{"title":"Discovery of an energy-dependent many-body process in the Kβ spectrum of manganese metal using extended-range high-energy-resolution fluorescence detection with advanced structural insights from principal component analysis","authors":"Jack Stephens , Ramesh Rijal , Daniel Sier , Nicholas T. T. Tran , Jonathan W. Dean , Paul Di Pasquale , Tony Kirk , Minh Dao , Chanh Q. Tran , Shusaku Hayama , Sofia Diaz-Moreno , Christopher T. Chantler","doi":"10.1107/S2052252525005573","DOIUrl":"10.1107/S2052252525005573","url":null,"abstract":"<div><div>A new satellite is discovered in the manganese <em>K</em>β spectrum using extended-range high-energy-resolution fluorescence detection. Advanced insights on its structure and evolution are extracted with principal component analysis.</div></div><div><div>The discovery of the novel <em>n</em> = 2 satellite transition in the <em>K</em>β emission spectrum of manganese and its evolution with incident photon energy are presented. Using the XR-HERFD (extended-range high-energy-resolution fluorescence detection) technique, we conclusively demonstrate the existence of this phenomenon with a statistical significance corresponding to 652 σ<sub>se</sub> across the measured spectrum, far above the discovery threshold of 3–6 σ<sub>se</sub>. We apply principal component analysis (PCA) to the XR-HERFD data to extract advanced structural insights. The evolution of this novel spectral feature and physical process are quantified by incorporating regression, revealing the increase in intensity over a wide range of incident photon energies. We validate these findings through independent test data. These results directly challenge the conventional treatment of the many-body reduction factor <em>S</em><sub>0</sub><sup>2</sup> as a constant independent of incident photon energy in the standard XAFS (X-ray absorption fine structure) equation. Thereby, these results present compelling evidence that <em>S</em><sub>0</sub><sup>2</sup> should be modelled as a varying function of incident photon energy, marking the first observation of this behaviour in <em>K</em>β spectra. This facilitates a greater quantitative understanding of HERFD spectra and a comprehensive representation of many-body effects in condensed matter systems.</div></div>","PeriodicalId":14775,"journal":{"name":"IUCrJ","volume":"12 5","pages":"Pages 548-562"},"PeriodicalIF":3.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144954895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IUCrJPub Date : 2025-09-01DOI: 10.1107/S2052252525007353
Michihiro Suga
{"title":"Illuminating DNA repair in action: structural insights into a photocaged glycosylase complex","authors":"Michihiro Suga","doi":"10.1107/S2052252525007353","DOIUrl":"10.1107/S2052252525007353","url":null,"abstract":"<div><div>Structural analysis of the co-crystal between human DNA glycosylase hOGG1 and a light-sensitive substrate analog highlights its utility as a platform for real-time observation of catalytic dynamics.</div></div>","PeriodicalId":14775,"journal":{"name":"IUCrJ","volume":"12 5","pages":"Pages 513-514"},"PeriodicalIF":3.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144954899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IUCrJPub Date : 2025-09-01DOI: 10.1107/S2052252525005871
Patrick Hautle , Oliver Zimmer , Hélène M. Jouve , Heinrich B. Stuhrmann
{"title":"Highlighting radical sites through polarized neutron scattering from AFP-modulated polarized protons","authors":"Patrick Hautle , Oliver Zimmer , Hélène M. Jouve , Heinrich B. Stuhrmann","doi":"10.1107/S2052252525005871","DOIUrl":"10.1107/S2052252525005871","url":null,"abstract":"<div><div>Selective nuclear spin reversal by the method of adiabatic fast passage is a way to order a system of dynamically polarized nuclei. Using polarized neutron scattering, it increases the visibility of sources and sinks of proton polarization in radical proteins. Notably, Tyr369 has been confirmed as a potential radical site in bovine liver catalase.</div></div><div><div>Time-resolved neutron scattering has been used to study dynamically polarized protons in tyrosyl-doped bovine liver catalase. While the evolution of proton polarization and its inversion by the method of adiabatic fast passage (AFP) in a standard dynamic nuclear polarization (DNP) system with organic Cr(V) complexes can be well modelled and understood, the experiments with tyrosyl-doped catalase lead us into the world of extremely dilute paramagnets with only about 10<sup>17</sup> unpaired electrons per cm<sup>3</sup>. In this regime, the strength of DNP is comparable to the drift of proton polarization towards its thermal equilibrium of <em>P</em><sub>e</sub> = 0.35% at <em>T</em> = 1 K and <em>B</em> = 3.5 T. Negative DNP, which counteracts this drift, is confined to protons very close to the radical site, typically within 5 Å. In contrast, AFP reverses the polarization of protons at a larger distance from the radical. The contrast of a domain of polarized close protons giving rise to neutron scattering is considerably enhanced by AFP. Moreover, the spread of proton polarization is sensitive to magnetic inhomogeneities, like the iron of the heme of the catalase molecule. In short, polarized neutron scattering from AFP-modulated polarized samples provides an excellent tool for mapping sources and sinks of proton polarization in radical proteins.</div></div>","PeriodicalId":14775,"journal":{"name":"IUCrJ","volume":"12 5","pages":"Pages 570-581"},"PeriodicalIF":3.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144954919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IUCrJPub Date : 2025-09-01DOI: 10.1107/S2052252525006220
Thorsten B. Blum , Karen M. Davies , Werner Kühlbrandt
{"title":"Subtomogram averages of mitochondrial ATP synthase dimers from plants show a conserved extra density at the peripheral stalk","authors":"Thorsten B. Blum , Karen M. Davies , Werner Kühlbrandt","doi":"10.1107/S2052252525006220","DOIUrl":"10.1107/S2052252525006220","url":null,"abstract":"<div><div>Electron cryo-tomography of ATP synthase dimers in plant mitochondria indicates a wide dimer angle and a plant-specific subunit in the peripheral stalk.</div></div><div><div>We analyzed ATP synthase dimers in mitochondria purified from four plant species by subtomogram averaging, using <em>Saccharomyces cerevisiae</em> as a control. The purified mitochondria were plunge-frozen and broken mitochondria were examined by electron cryo-tomography. In each case, the ATP synthase dimers formed extensive rows along the tightly curved cristae ridges. ATP synthase dimer particles of each species were picked and averaged. Subtomogram averages of all four plant ATP synthases revealed an extra density at the tip of the peripheral stalk next to the OSCP hinge that is not seen in <em>S. cerevisae.</em> The dimer angle between the ATP synthase monomers is wider than in <em>Polytomella</em>, <em>S. cerevisae</em> or mammals, but less wide than in <em>Caenorhabditis elegans</em>. Slight variations in dimer angle indicate that ATP synthase dimers of plant mitochondria are more flexible than others.</div></div>","PeriodicalId":14775,"journal":{"name":"IUCrJ","volume":"12 5","pages":"Pages 563-569"},"PeriodicalIF":3.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144954951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IUCrJPub Date : 2025-09-01DOI: 10.1107/S2052252525006785
Eliška Zmeškalová , Tereza Havlůjová , Martin Babor , Marcela Tkadlecová , Jaroslav Havlíček , Tomáš Pekárek , Szymon Tomczak , Luděk Ridvan , Miroslav Šoóš
{"title":"Unravelling venetoclax solvate behaviour: insights from crystal structures and computational surface analysis","authors":"Eliška Zmeškalová , Tereza Havlůjová , Martin Babor , Marcela Tkadlecová , Jaroslav Havlíček , Tomáš Pekárek , Szymon Tomczak , Luděk Ridvan , Miroslav Šoóš","doi":"10.1107/S2052252525006785","DOIUrl":"10.1107/S2052252525006785","url":null,"abstract":"<div><div>Seven venetoclax solvates were structurally characterized and studied for their desolvation behaviour, leading to the identification of two solvent-free polymorphs. Advanced crystallographic and computational analyses, including <em>Solvate Analyser</em>, <em>CSD-Particle</em>, FTIR and solid-state NMR, revealed key factors governing solvate stability and transformation. Notably, the acetone solvate exhibited exceptional stability and the desolvated forms retained the molecular arrangement of their parent solvates.</div></div><div><div>This study investigates venetoclax solvates and their nonsolvated forms through desolvation. Seven solvates were prepared and their structures solved from single-crystal X-ray diffraction data. Among these, two are cavity solvates while the remaining five are channel solvates, with three being isomorphous. Desolvation experiments led to two solvent-free crystalline polymorphs of venetoclax, forms A and B. Notably, the acetone solvate remained stable and did not convert to a nonsolvated form. Form B has a higher melting point and a faster intrinsic dissolution rate than form A. Advanced computational tools, including <em>Solvate Analyser</em> and <em>CSD-Particle</em>, provided insights into crystal surface properties and desolvation behaviour. Properties such as lattice energy, molecular interaction energy, attachment energy, surface rugosity and solvent arrangement within the crystal and on the surface were linked to solvate stability and subsequent transformation upon desolvation. A combination of FTIR, and <sup>13</sup>C and <sup>15</sup>N solid-state NMR spectroscopies showed that both short- and long-range molecular interactions and arrangements of venetoclax molecules in the desolvated forms closely resembled those in the parent solvates.</div></div>","PeriodicalId":14775,"journal":{"name":"IUCrJ","volume":"12 5","pages":"Pages 595-609"},"PeriodicalIF":3.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144954963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IUCrJPub Date : 2025-09-01DOI: 10.1107/S205225252500538X
Adam F. Sapnik , Philip A. Chater , Dean S. Keeble , John S. O. Evans , Federica Bertolotti , Antonietta Guagliardi , Lise J. Støckler , Elodie A. Harbourne , Anders B. Borup , Rebecca S. Silberg , Adrien Descamps , Clemens Prescher , Benjamin D. Klee , Axel Phelipeau , Imran Ullah , Kárel G. Medina , Tobias A. Bird , Viktoria Kaznelson , William Lynn , Andrew L. Goodwin , David A. Keen
{"title":"High-quality ultra-fast total scattering and pair distribution function data using an X-ray free-electron laser","authors":"Adam F. Sapnik , Philip A. Chater , Dean S. Keeble , John S. O. Evans , Federica Bertolotti , Antonietta Guagliardi , Lise J. Støckler , Elodie A. Harbourne , Anders B. Borup , Rebecca S. Silberg , Adrien Descamps , Clemens Prescher , Benjamin D. Klee , Axel Phelipeau , Imran Ullah , Kárel G. Medina , Tobias A. Bird , Viktoria Kaznelson , William Lynn , Andrew L. Goodwin , David A. Keen","doi":"10.1107/S205225252500538X","DOIUrl":"10.1107/S205225252500538X","url":null,"abstract":"<div><div>This work demonstrates that high-quality ultra-fast total scattering data and pair distribution function data can be obtained from a single ∼30 fs pulse at the European XFEL, achieving a record <em>Q</em> range of up to 16.6 Å<sup>−1</sup>. These results establish XFELs as powerful tools for probing atomic scale structures on ultra-fast timescales, opening new opportunities for studying dynamic processes in disordered and complex materials.</div></div><div><div>High-quality total scattering data, a key tool for understanding atomic-scale structure in disordered materials, require stable instrumentation and access to high momentum transfers. This is now routine at dedicated synchrotron instrumentation using high-energy X-ray beams, but it is very challenging to measure a total scattering dataset in less than a few microseconds. This limits their effectiveness for capturing structural changes that occur at the much faster timescales of atomic motion. Current X-ray free-electron lasers (XFELs) provide femtosecond-pulsed X-ray beams with maximum energies of ∼24 keV, giving the potential to measure total scattering and the attendant pair distribution functions (PDFs) on femtosecond timescales. We demonstrate that this potential has been realized using the HED scientific instrument at the European XFEL and present normalized total scattering data for 0.35 Å<sup>−1</sup> < <em>Q</em> < 16.6 Å<sup>−1</sup> and their PDFs from a broad spectrum of materials, including crystalline, nanocrystalline and amorphous solids, liquids and clusters in solution. We analyzed the data using a variety of methods, including Rietveld refinement, small-box PDF refinement, joint reciprocal–real-space refinement, cluster refinement and Debye scattering analysis. The resolution function of the setup is also characterized. We conclusively show that high-quality data can be obtained from a single ∼30 fs XFEL pulse for multiple different sample types. Our efforts not only significantly increase the existing maximum reported <em>Q</em> range for an <em>S</em>(<em>Q</em>) measured at an XFEL but also mean that XFELs are now a viable X-ray source for the broad community of people using reciprocal-space total scattering and PDF methods in their research.</div></div>","PeriodicalId":14775,"journal":{"name":"IUCrJ","volume":"12 5","pages":"Pages 531-547"},"PeriodicalIF":3.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144690290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
IUCrJPub Date : 2025-09-01DOI: 10.1107/S2052252525006645
Peter Smyth , Sofia Jaho , Lewis J. Williams , Gabriel Karras , Ann Fitzpatrick , Amy J. Thompson , Sinan Battah , Danny Axford , Sam Horrell , Marina Lučić , Kotone Ishihara , Machika Kataoka , Hiroaki Matsuura , Kanji Shimba , Kensuke Tono , Takehiko Tosha , Hiroshi Sugimoto , Shigeki Owada , Michael A. Hough , Jonathan A.R. Worrall , Robin L. Owen
{"title":"Time-resolved serial synchrotron and serial femtosecond crystallography of heme proteins using photocaged nitric oxide","authors":"Peter Smyth , Sofia Jaho , Lewis J. Williams , Gabriel Karras , Ann Fitzpatrick , Amy J. Thompson , Sinan Battah , Danny Axford , Sam Horrell , Marina Lučić , Kotone Ishihara , Machika Kataoka , Hiroaki Matsuura , Kanji Shimba , Kensuke Tono , Takehiko Tosha , Hiroshi Sugimoto , Shigeki Owada , Michael A. Hough , Jonathan A.R. Worrall , Robin L. Owen","doi":"10.1107/S2052252525006645","DOIUrl":"10.1107/S2052252525006645","url":null,"abstract":"<div><div>We demonstrate the application of a nitric oxide releasing photocage system for time-resolved serial crystallography studies of two heme containing proteins using a fixed target sample delivery system. Optimal parameters for successful photocage activation and nitric oxide release are explored.</div></div><div><div>Time-resolved X-ray crystallography is undergoing a renaissance due to the development of serial crystallography at synchrotron and XFEL beamlines. Crucial to such experiments are efficient and effective methods for uniformly initiating time-dependent processes within microcrystals, such as ligand binding, enzymatic reactions or signalling. A widely applicable approach is the use of photocaged substrates, where the photocage is soaked into the crystal in advance and then activated using a laser pulse to provide uniform initiation of the reaction throughout the crystal. This work characterizes photocage release of nitric oxide and binding of this ligand to two heme protein systems, cytochrome <em>c</em>′-β and dye-decolourizing peroxidase B using a fixed target sample delivery system. Laser parameters for photoactivation are systematically explored, and time-resolved structures over timescales ranging from 100 µs to 1.4 s using synchrotron and XFEL beamlines are described. The effective use of this photocage for time-resolved crystallography is demonstrated and appropriate illumination conditions for such experiments are determined.</div></div>","PeriodicalId":14775,"journal":{"name":"IUCrJ","volume":"12 5","pages":"Pages 582-594"},"PeriodicalIF":3.6,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144954930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}