Conformation sequence recovery of a non-periodic object from a diffraction-before-destruction experiment

Chun Hong Yoon,Richard J Bean,Richard A Kirian,Emanuele Pedersoli,Maya Kiskinova,Francesco Stellato,Lorenzo Raimondi,Fenglin Wang,Flavio Capotondi,Miriam Barthelmess,Henry N Chapman

doi:10.1364/oe.22.008085

Abstract

Knowledge of the sequence of different conformational states of a protein molecule is key to better understanding its biological function. A diffraction pattern from a single conformational state can be captured with an ultrafast X-ray Free-Electron Laser (XFEL) before the target is completely annihilated by the radiation. In this paper, we report the first experimental demonstration of conformation sequence recovery using diffraction patterns from randomly ordered conformations of a non-periodic object using the dimensional reduction technique Isomap and coherent diffraction imaging.

Highlights

A diffraction pattern from a single conformational state can be captured with an ultrafast X-ray Free-Electron Laser (XFEL) before the target is completely annihilated by the radiation
A diffraction pattern from a non-periodic object such as a large macromolecule or a virus may be captured by an ultrafast X-ray Free-Electron Laser (XFEL) before the target is completely annihilated by the radiation
We report the experimental demonstration of conformation sequence recovery using diffraction patterns from random instances of single micro-fabricated objects illuminated by soft X-ray FEL pulses

Summary

Introduction

A diffraction pattern from a non-periodic object such as a large macromolecule or a virus may be captured by an ultrafast X-ray Free-Electron Laser (XFEL) before the target is completely annihilated by the radiation. This so called “Diffraction-before-destruction” technique [1,2] requires coherent X-ray pulses with higher peak brilliance than modern synchrotron sources can produce. The emergence of hard XFELs has enabled structural studies of nano-structured single particles [5,6,7] and microcrystals [8,9]. A pump-probe experiment at LCLS showed it may be possible to probe the conformational states of the structure of Photosystem II microcrystals [10] at particular times after exposure to an optical pulse

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Conclusion