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Towards phasing using high X-ray intensity.

ABSTRACT: X-ray free-electron lasers (XFELs) show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential 'bleaching' of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected from a Gd derivative of lysozyme microcrystals at different X-ray intensities, and the degree of ionization of Gd atoms is quantified from phased difference Fourier maps. A pattern sorting scheme is proposed to maximize the ionization contrast and the way in which the local electronic damage can be used for a new experimental phasing method is discussed.

SUBMITTER: Galli L

PROVIDER: S-EPMC4645107 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature

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Towards phasing using high X-ray intensity.

Galli Lorenzo L Son Sang-Kil SK Barends Thomas R M TR White Thomas A TA Barty Anton A Botha Sabine S Boutet Sébastien S Caleman Carl C Doak R Bruce RB Nanao Max H MH Nass Karol K Shoeman Robert L RL Timneanu Nicusor N Santra Robin R Schlichting Ilme I Chapman Henry N HN

IUCrJ 20150930 Pt 6

X-ray free-electron lasers (XFELs) show great promise for macromolecular structure determination from sub-micrometre-sized crystals, using the emerging method of serial femtosecond crystallography. The extreme brightness of the XFEL radiation can multiply ionize most, if not all, atoms in a protein, causing their scattering factors to change during the pulse, with a preferential 'bleaching' of heavy atoms. This paper investigates the effects of electronic damage on experimental data collected fr ...[more]

PMID: 26594370

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