کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5914586 1162743 2012 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Automatic magnification determination of electron cryomicroscopy images using apoferritin as a standard
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شناسی مولکولی
پیش نمایش صفحه اول مقاله
Automatic magnification determination of electron cryomicroscopy images using apoferritin as a standard
چکیده انگلیسی

Interpretation of the structural information in cryomicroscopy images recorded on film or CCD camera requires a precise knowledge of the electron microscope parameters that affect image features such as magnification and defocus. Magnification must be determined in order to combine data from different images in a three-dimensional reconstruction and to accurately scale reconstructions for fitting with atomic resolution models. A method is described for estimating the absolute magnification of an electron micrograph of a frozen-hydrated specimen using horse spleen apoferritin as a standard. Apoferritin is a widely available protein complex of known structure that may be included with the specimen of interest and imaged under conditions identical to those used for imaging other biological specimens by cryomicroscopy. The sum of the structure factor intensities of images of randomly-oriented apoferritin particles shows three low resolution peaks to 25 Å that arise from the hollow ball structure of apoferritin. Comparison of peak positions of the experimental intensities with structure factor intensities of an atomic model of apoferritin determined by X-ray crystallography provides a scale factor for estimating the absolute magnification of the micrograph. We compare the magnification estimate using apoferritin to that obtained with tobacco mosaic virus, another common magnification standard for cryomicroscopy. We verify the precision of the method by acquiring images with a systematic variation of magnification.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Structural Biology - Volume 180, Issue 1, October 2012, Pages 243-248
نویسندگان
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