Ma, Shumeng;
Mykhaylyk, Vitaliy;
Bowler, Matthew W;
Pinotsis, Nikos;
Kozielski, Frank;
(2023)
High-Confidence Placement of Fragments into Electron Density Using Anomalous Diffraction—A Case Study Using Hits Targeting SARS-CoV-2 Non-Structural Protein 1.
International Journal of Molecular Sciences
, 24
(13)
, Article 11197. 10.3390/ijms241311197.
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Abstract
The identification of multiple simultaneous orientations of small molecule inhibitors binding to a protein target is a common challenge. It has recently been reported that the conformational heterogeneity of ligands is widely underreported in the Protein Data Bank, which is likely to impede optimal exploitation to improve affinity of these ligands. Significantly less is even known about multiple binding orientations for fragments (<300 Da), although this information would be essential for subsequent fragment optimisation using growing, linking or merging and rational structure-based design. Here, we use recently reported fragment hits for the SARS-CoV-2 non-structural protein 1 (nsp1) N-terminal domain to propose a general procedure for unambiguously identifying binding orientations of 2-dimensional fragments containing either sulphur or chloro substituents within the wavelength range of most tunable beamlines. By measuring datasets at two energies, using a tunable beamline operating in vacuum and optimised for data collection at very low X-ray energies, we show that the anomalous signal can be used to identify multiple orientations in small fragments containing sulphur and/or chloro substituents or to verify recently reported conformations. Although in this specific case we identified the positions of sulphur and chlorine in fragments bound to their protein target, we are confident that this work can be further expanded to additional atoms or ions which often occur in fragments. Finally, our improvements in the understanding of binding orientations will also serve to improve the rational optimisation of SARS-CoV-2 nsp1 fragment hits
| Type: | Article |
|---|---|
| Title: | High-Confidence Placement of Fragments into Electron Density Using Anomalous Diffraction—A Case Study Using Hits Targeting SARS-CoV-2 Non-Structural Protein 1 |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3390/ijms241311197 |
| Publisher version: | https://doi.org/10.3390/ijms241311197 |
| Language: | English |
| Additional information: | © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
| Keywords: | SARS-CoV-2; COVID-19; non-structural proteins; nsp1; tunable wavelength; fragment orientation; anomalous difference Fourier map |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > UCL School of Pharmacy UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > UCL School of Pharmacy > Pharma and Bio Chemistry |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10173847 |
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