Tools for the cryo-EM gold rush: going from the cryo-EM map to the atomistic model

As cryo electron microscopy (Cryo-EM) enters mainstream structural biology, the demand for fitting methods is high. Here, we explain the importance of flexible fitting for Cryo-EM, potential concerns and assessment methods of this approach, and review existing methods. We aim to give readers concrete descriptions of Cryo-EM flexible fitting methods with corresponding examples.