2.85 and 2.99 Å resolution structures of 110 kDa nitrite reductase determined by 200 kV cryogenic electron microscopy

GoToCloud optimization of cloud computing environment for accelerating cryo-EM structure-based drug design

Cryogenic electron microscopy (Cryo-EM) is a widely used technique for visualizing the 3D structures of many drug design targets, including membrane proteins, at atomic resolution. However, the necessary throughput for structure-based drug design (SBDD) is not yet achieved. Currently, data analysis is a major bottleneck due to the rapid advancements in detector technology and image acquisition methods. Here we show "GoToCloud", a cloud-computing-based platform for advanced data analysis and data management in Cryo-EM. With GoToCloud, it is possible to optimize computing resources and reduce costs by selecting the most appropriate parallel processing settings for each processing step. Our benchmark tests on GoToCloud demonstrate that parallel computing settings, including the choice of computational hardware, as well as a required target resolution have significant impacts on the processing time and cost performance. Through this optimization of a cloud computing environment, GoToCloud emerges as a promising platform for the acceleration of Cryo-EM SBDD.

High-resolution cryo-EM performance comparison of two latest-generation cryo electron microscopes on the human ribosome

Recent technological advances in cryo electron microscopy (cryo-EM) have led to new opportunities in the structural biology field. Here we benchmark the performance of two 300 kV latest-generation cryo electron microscopes, Titan Krios G4 from Thermofisher Scientific and CRYO ARM 300 from Jeol, with regards to achieving high resolution single particle reconstructions on a real case sample. We compare potentially limiting factors such as drift rates, astigmatism & coma aberrations and performance during image processing and show that both microscopes, while comprising rather different technical setups & parameter settings and equipped with different types of energy filters & cameras, achieve a resolution of around 2 Å on the human ribosome, a non-symmetric object which constitutes a key drug target. Astigmatism correction, CTF refinement and correction of higher order aberrations through refinement in separate optics groups helped to account for astigmatism/coma caused by beam tilting during multi-spot and multi-hole acquisition in neighbouring holes without stage movement. The obtained maps resolve Mg²⁺ ions, water molecules, inhibitors and side-chains including chemical modifications. The fact that both instruments can resolve such detailed features will greatly facilitate understanding molecular mechanisms of various targets and helps in cryo-EM structure based drug design. The methods and analysis tools used here will be useful also to characterize existing instruments and optimize data acquisition settings and are applicable broadly to other drug targets in structural biology.