کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2829483 | 1162810 | 2007 | 11 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Application of the iterative helical real-space reconstruction method to large membranous tubular crystals of P-type ATPases Application of the iterative helical real-space reconstruction method to large membranous tubular crystals of P-type ATPases](/preview/png/2829483.png)
Since the development of three-dimensional helical reconstruction methods in the 1960’s, advances in Fourier–Bessel methods have facilitated structure determination to near-atomic resolution. A recently developed iterative helical real-space reconstruction (IHRSR) method provides an alternative that uses single-particle analysis in conjunction with the imposition of helical symmetry. In this work, we have adapted the IHRSR algorithm to work with frozen-hydrated tubular crystals of P-type ATPases. In particular, we have implemented layer-line filtering to improve the signal-to-noise ratio, Wiener-filtering to compensate for the contrast transfer function, solvent flattening to improve reference reconstructions, out-of-plane tilt compensation to deal with flexibility in three dimensions, systematic calculation of Fourier shell correlations to track the progress of the refinement, and tools to control parameters as the refinement progresses. We have tested this procedure on datasets from Na+/K+-ATPase, rabbit skeletal Ca2+-ATPase and scallop Ca2+-ATPase in order to evaluate the potential for sub-nanometer resolution as well as the robustness in the presence of disorder. We found that Fourier–Bessel methods perform better for well-ordered samples of skeletal Ca2+-ATPase and Na+/K+-ATPase, although improvements to IHRSR are discussed that should reduce this disparity. On the other hand, IHRSR was very effective for scallop Ca2+-ATPase, which was too disordered to analyze by Fourier–Bessel methods.
Journal: Journal of Structural Biology - Volume 157, Issue 1, January 2007, Pages 106–116