The condensin holocomplex cycles dynamically between open and collapsed states

• Published in: Nature structural & molecular biology Vol. 27; no. 12; pp. 1134 - 1141
• Main Authors: Ryu, Je-Kyung, Katan, Allard J., van der Sluis, Eli O., Wisse, Thomas, de Groot, Ralph, Haering, Christian H., Dekker, Cees
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01-12-2020; Nature Publishing Group
• Subjects: 631/337/386; 631/535/1262; 631/57/2265; Adenosine Triphosphatases - chemistry; Adenosine Triphosphatases - genetics; Adenosine Triphosphatases - metabolism; Adenosine Triphosphate - chemistry; Adenosine Triphosphate - metabolism; Atomic force microscopy; Biochemistry; Biological Microscopy; Biomedical and Life Sciences; Cell Cycle Proteins - chemistry; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; Cellular proteins; Chromosomal Proteins, Non-Histone - chemistry; Chromosomal Proteins, Non-Histone - genetics; Chromosomal Proteins, Non-Histone - metabolism; Chromosomes; Chromosomes, Fungal - metabolism; Chromosomes, Fungal - ultrastructure; Condensin; Deoxyribonucleic acid; DNA; DNA, Fungal - chemistry; DNA, Fungal - genetics; DNA, Fungal - metabolism; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Domains; Extrusion; Fungal Proteins - chemistry; Fungal Proteins - genetics; Fungal Proteins - metabolism; Gene Expression; Life Sciences; Membrane Biology; Microscopy; Microscopy, Atomic Force; Molecular motors; Multiprotein Complexes - chemistry; Multiprotein Complexes - genetics; Multiprotein Complexes - metabolism; Nuclear Proteins - chemistry; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Nucleic Acid Conformation; Properties; Protein Binding; Protein Conformation; Protein research; Protein Structure; Proteins; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae - ultrastructure; Saccharomyces cerevisiae Proteins - chemistry; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Structure; Switching; Yeast; Yeasts; Netherlands
• ISSN: 1545-9993; 1545-9985
• DOI: 10.1038/s41594-020-0508-3

Structural maintenance of chromosome (SMC) protein complexes are the key organizers of the spatiotemporal structure of chromosomes. The condensin SMC complex has recently been shown to be a molecular motor that extrudes large loops of DNA, but the mechanism of this unique motor remains elusive. Using atomic force microscopy, we show that budding yeast condensin exhibits mainly open ‘O’ shapes and collapsed ‘B’ shapes, and it cycles dynamically between these two states over time, with ATP binding inducing the O to B transition. Condensin binds DNA via its globular domain and also via the hinge domain. We observe a single condensin complex at the stem of extruded DNA loops, where the neck size of the DNA loop correlates with the width of the condensin complex. The results are indicative of a type of scrunching model in which condensin extrudes DNA by a cyclic switching of its conformation between O and B shapes.
Atomic force microscopy imaging of yeast condensin indicates that condensin may extrude DNA by switching conformation between open O and collapsed B shapes, indicative of a type of scrunching model.