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Title Protein crystals can be incommensurately modulated
Author/s Jeffrey J Lovelace, Cameron R Murphy, Lee Daniels, Kartik Narayan, Clarence E Schutt, Uno Lindberg, Christer Svensson, Gloria E. O. Borgstahl
Department/s Max-laboratory
Full-text Full text is not available in this archive
Alternative location (URL) http://dx.doi.org/10.1107/S002... Restricted Access (Alternative Location)
Publication/Series Journal of Applied Crystallography
Publishing year 2008
Volume 41
Issue Part 3
Pages 600 - 605
Document type Journal article
Status published
Quality controlled yes
Language English
Publisher Blackwell Publishing
Abstract English For a normal periodic crystal, the X-ray diffraction pattern can be described by an orientation matrix and a set of three integers that indicate the reciprocal lattice points. Those integers determine the spacing along the reciprocal lattice directions. In aperiodic crystals, the diffraction pattern is modulated and the standard periodic main reflections are surrounded by satellite reflections. The successful indexing and refinement of the main unit cell and q vector using TWINSOLVE, developed by Svensson [(2003). Lund University, Sweden], are reported here for an incommensurately modulated, aperiodic crystal of a profilin: actin complex. The indexing showed that the modulation is along the b direction in the crystal, which corresponds to an 'actin ribbon' formed by the crystal lattice. Interestingly, the transition to the aperiodic state was shown to be reversible and the diffraction pattern returned to the periodic state during data collection. It is likely that the protein underwent a conformational change that affected the neighbouring profilin: actin molecules in such a way as to produce the observed modulation in the diffraction pattern. Future work will aim to trap the incommensurately modulated crystal state, for example using cryocooling or chemical crosslinking, thus allowing complete X-ray data to be collected.
Subject Chemistry
Medicine and Health Sciences
Keywords profilin, modulated protein crystals, actin, modulated diffraction, satellite reflections, incommensurate crystallography
ISBN/ISSN/Other ISSN: 0021-8898

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