Annuaire
Specific Xray diffraction patterns of membrane proteins caused by secondary structure collinearity.
Biochim Biophys Acta Biomembr, 1865(1):184065.
Diffraction anisotropy is a phenomenon that impacts more specifically membraneproteins, compared to soluble ones, but the reasons for this discrepancy remainedunclear. Often, it is referred to a difference in resolution limits betweenhighest and lowest diffraction limits as a signature for anisotropy. We show inthis article that there is no single correlation between anisotropy anddifference in resolution limits, with notably a substantial number of structuresdisplaying various anisotropy with no difference in resolution limits. We furtherinvestigated diffraction intensity profiles, and observed a peak centred on 4.9 Åresolution more predominant in membrane proteins. Since this peak is in theregion corresponding to secondary structures, we investigated the influence ofsecondary structure ratio. We showed that secondary structure content has littleinfluence on this profile, while secondary structure collinearity in membraneproteins correlate with a stronger peak. Finally, we could further show that thepresence of this peak is linked to higher diffraction anisotropy. These resultsbring to light a specific diffraction of membrane protein crystals, which callsfor a specific handling by crystallographic software. It also brings anexplanation for investigators struggling with their anisotropic data.
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