BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:MAX4Life Talk: Towards Routine Quantum Crystallography of Biologic al Macromolecules DTSTART:20260513T093000Z DTEND:20260513T103000Z DTSTAMP:20260514T035300Z UID:indico-event-5934@indico.maxiv.lu.se DESCRIPTION:Warm welcome to Dr. Ashwin Chari from MPI\, Göttingen as our next speaker in the MAX4Life Talk Series for Spring 2026!\nThe MAX4Life se ries highlights innovative and impactful Life Science research through rou ghly one-hour talks\, followed by Q&A and informal mingling with the MAX I V community.\nTalk Title: Towards Routine Quantum Crystallography of Biolo gical Macromolecules\n\nSpeaker: Dr. Ashwin Chari\nTime & Date: 11:30 to 12:30\, Wednesday\, May 13\nLocation: meeting room MAX III\, MAX IV Labora tory\nRegistration: Registration is for individuals who are not affiliated with MAX IV and would like to attend the talk in person at the MAX IV fac ility. It is free of charge\nDeadline for registration: 11:30 am Tuesday\, May 12\nPlease use the Zoom Link if attending remotely.\nAbstract:\n\n\nT owards Routine Quantum Crystallography of Biological Macromolecules\nAshwi n Chari1\,*\, Elham Paknia1\, Claus Flensburg2\, Clemens Vonrhein2\, Rasmu s Fogh2\, Peter Keller2\, Thomas R. Schneider3\, Clemens Schulze-Briese4\, Michal Chodkiewicz5\, Paulina Dominiak5\, Gleb Bourenkov3\, Gérard Brico gne2\n(1) Research Group for Structural Biochemistry and Mechanisms\, Max Planck Institute for Biophysical Chemistry\, Am Fassberg 11\, D-37077 Göt tingen\, Germany\; (2) Global Phasing Limited\, Sheraton House\, Castle Pa rk\, Cambridge CB3 0AX\, UK\; (3) EMBL Hamburg Unit c/o DESY\, European Mo lecular Biology Laboratory\, Notkestrasse 85\, 22607 Hamburg\, Germany\; ( 4) DECTRIS Ltd. Täfernweg 1\, 5405 Baden-Dättwil\, Switzerland\; (5) Bio logical and Chemical Research Centre\, Department of Chemistry\, Universit y of Warsaw\, ul. Zwirki I Wigury 101\, Warsaw\, 02-089\, Poland. \nCorres ponding author: ashwin.chari@mpinat.mpg.de\nKeywords: sub-Ångström reso lution\, macromolecular crystallography\, radiation damage\, structural en zymology\, Quantum Crystallography\nThis presentation consists of two part s. First\, I introduce a novel concept of high-energy data acquisition wit h a highly optimized setup and workflow for protein crystallography. The s etup is implemented at the EMBL beamline P14 at the PETRA III storage ring at DESY (Hamburg\, Germany). It delivers variable-size top-hat beams\, th at are particularly important in structural studies of large macromolecula r complexes [1\,2] and in ultra-high-resolution studies of enzymatic mecha nisms under precise dose control. The combination of a high-flux collimate d mode with a detector of high quantum efficiency at 26.687 keV increases data quality by reducing radiation damage and enhancing the Signal-to-Nois e ratio [3]. To further improve data quality\, Global Phasing Ltd.’s wor kflow has been deployed on P14 through its interface to MXCuBE2 ([4]\, § 4.4.7). Crystal symmetry and orientation are first determined\, then used together with knowledge of the MD3-goniostat’s reorientation capabilitie s to design a multi-orientation strategy aiming at achieving completeness (no cusps) and uniformity of redundancy\, within a “dose budget” adapt ed to the target resolution [5]. The workflow then directly drives the exe cution of that strategy via MXCuBE2.\nIn the second part\, I will present how the implementation of these procedures allows us to routinely collect single-crystal datasets at atomic and sub-Å resolution. The precision of these datasets and the accuracy of the models derived from them effectivel y allow us to achieve single-electron accuracy in protein X-ray crystallog raphy. This has enabled us to assess the impact of radiation damage in sub -Å resolution datasets. A first study at 0.55 Å resolution reveals exten sive small conformational changes in response to dose [6]. We have also de termined a 0.43 Å structure of Rubredoxin which reveals 50% of the bond m id-point electron densities between all second-row element atoms in the st ructure. By connecting the DiSCaMB library [7] to BUSTER [8]\, we are able to use transferable aspherical atom model (TAAM) for the refinement of su b-Å protein structures. This enables a direct visualization of enzyme act ive sites and enzymatic reaction mechanisms by means of cryo-trapped snaps hots. On the basis of these new insights\, we are forced to redefine the c hemical structure of several enzyme active sites and revise enzymatic reac tion mechanisms. I will discuss how the accurate\, detailed visualization of a wide variety of enzyme reaction mechanisms will benefit from highly p recise crystallographic data together with TAAM and/or other forms of asph erical atom refinement.\nReferences\n[1] Schrader et al. (2016) Science 35 3\, 594-598.\n[2] Singh et al. (2020) Cell 180\, 1130-1143.\n[3] Storm et al. (2021) IUCrJ 8(6)\n[4] Oscarsson et al. (2019) Journal of Synchrotron Radiation 26\, 393-405.\n[5] Fogh et al. (2026) Acta Cryst D\, submitted\n [6] Bourenkov et al. (2026) Acta Cryst D\, submitted\n[7] https://github.c om/discamb-project/DiSCaMB\n[8] Bricogne et al. (2017) BUSTER version 202 5-07-17 Cambridge UK\, Global Phasing Ltd.\n\n\n \n\n \n\nhttps://indico .maxiv.lu.se/event/5934/ LOCATION:MAX III (MAX IV) URL:https://indico.maxiv.lu.se/event/5934/ END:VEVENT END:VCALENDAR