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SciLifeLab seminar series-Campus Solna, Rouslan Efremov, From cryo-EM map to model

Wednesday, August 14

Rouslan Efremov

Vrije Universiteit Brussels, Belgium

Rouslan Efremov obtained ​PhD in physics in 2005 from Moscow Institute for Physics and Technology. He did a postdoc at the MRC Mitochondrial Biology Unit, Cambridge, UK, where he solved the X-ray crystal structure of the respiratory complex I (Nature: 476, 2011). During a second postdoc at Max Planck Institute for Molecular Physiology, Dortmund, Germany, he revealed the mechanism of the Tc toxin (Nature: 508, 2014) and acquired cryo-EM expertise applying it to the membrane ryanodine receptor in nanodisc (Nature: 517, 2015). As a group leader at VIB Brussels, Rouslan established the cryo-EM facility and currently focuses on methods development and characterisation of dynamic membrane proteins.

Title: From cryo-EM map to model: building and refining models at near atomic resolution

Single particle cryo-EM density maps are often determined at resolution of around 3.5 Å and lower. Moreover, the resolution of EM density maps is often non-homogeneous, with regions of the maps determined at medium and low resolution. Such properties of the EM maps present a number of challenges for model building and refinement. In the lecture, the properties of the EM density maps will be discussed. I will outline approaches that can be used for building a model into medium and low-resolution density maps. The model building will be illustrated on examples of large protein complexes, including respiratory complex I and ryanodine receptor, determined at resolution between 3 and 6 Å. The ambiguities of the models will be discussed and practical approaches for model validation will be presented.

Host: A. Amunts,