A Transient and Low-Populated Protein-Folding Intermediate at Atomic Resolution

Abstract

Transient Protein Conformations Transient conformations are important to protein function; however, detecting and characterizing these states is technically challenging. Korzhnev et al. (p. 1312 ; see the Perspective by Al-Hashimi ) combined recently developed methods to determine the three-dimensional atomic-resolution structure of a transient intermediate of a four-helix bundle protein domain. The intermediate formed rapidly but, owing to structural peculiarities, slowly rearranged into its native state. The methods can be applied not only to folding intermediates but also to excited states important for protein function.