Minimizing Crinkling of Soft Specimens Using Holey Gold Films on Molybdenum Grids for Cryogenic Electron Microscopy. (August 2021)

• Record Type: Journal Article
• Authors: Jiang, Xi; Xuan, Sunting; Zuckermann, Ronald N.; Glaeser, Robert M.; Downing, Kenneth H.; Balsara, Nitash P.
• Is Part Of: Microscopy and microanalysis. Volume 27:Number 4(2021)
• Page Start: 767
• Page End: 775
• Publication Date: 2021-08
• Subjects: cryo-crinkling -- cryo-EM -- crystalline polypeptoid membranes -- crystallography -- specimen flatness; Microscopy -- Periodicals; Microchemistry -- Periodicals; 502.82
• DOI: 10.1017/S1431927621000520
• Languages: English
• ISSNs: 1431-9276

Abstract

Abstract: Abstract : We introduce a novel composite holey gold support that prevents cryo-crinkling and reduces beam-induced motion of soft specimens, building on the previously introduced all-gold support. The composite holey gold support for high-resolution cryogenic electron microscopy of soft crystalline membranes was fabricated in two steps. In the first step, a holey gold film was transferred on top of a molybdenum grid. In the second step, a continuous thin carbon film was transferred onto the holey gold film. This support (Au/Mo grid) was used to image crystalline synthetic polymer membranes. The low thermal expansion of Mo is not only expected to avoid cryo-crinkling of the membrane when the grids are cooled to cryogenic temperatures, but it may also act to reduce whatever crinkling existed even before cooling. The Au/Mo grid exhibits excellent performance with specimens tilted to 45°. This is demonstrated by quantifying beam-induced motion and differences in local defocus values. In addition, images of specimens on the Au/Mo grids that are tilted at 45° show high-resolution information of the crystalline membranes that, after lattice-unbending, extends beyond 1.5 Å in the direction perpendicular to the tilt axis.