8I13

Cryo-EM structure of 6-subunit Smc5/6

Summary for 8I13

• Entry DOI: 10.2210/pdb8i13/pdb
• EMDB information: 35116
• Descriptor: SMC6 isoform 1, Structural maintenance of chromosomes protein 5, MMS21 isoform 1, ... (6 entities in total)
• Functional Keywords: cell cycle
• Biological source: Saccharomyces cerevisiae (baker's yeast); More
• Total number of polymer chains: 6
• Total formula weight: 403400.09

Authors

Qian, L.,Jun, Z.,Xiang, Z.,Cheng, T.,Zhaoning, W.,Duo, J.,Zhenguo, C.,Wang, L. (deposition date: 2023-01-12, release date: 2024-06-26, Last modification date: 2024-10-30)

Primary citation

Li, Q.,Zhang, J.,Haluska, C.,Zhang, X.,Wang, L.,Liu, G.,Wang, Z.,Jin, D.,Cheng, T.,Wang, H.,Tian, Y.,Wang, X.,Sun, L.,Zhao, X.,Chen, Z.,Wang, L.
Cryo-EM structures of Smc5/6 in multiple states reveal its assembly and functional mechanisms.
Nat.Struct.Mol.Biol., 31:1532-1542, 2024

PubMed Abstract: Smc5/6 is a member of the eukaryotic structural maintenance of chromosomes (SMC) family of complexes with important roles in genome maintenance and viral restriction. However, limited structural understanding of Smc5/6 hinders the elucidation of its diverse functions. Here, we report cryo-EM structures of the budding yeast Smc5/6 complex in eight-subunit, six-subunit and five-subunit states. Structural maps throughout the entire length of these complexes reveal modularity and key elements in complex assembly. We show that the non-SMC element (Nse)2 subunit supports the overall shape of the complex and uses a wedge motif to aid the stability and function of the complex. The Nse6 subunit features a flexible hook region for attachment to the Smc5 and Smc6 arm regions, contributing to the DNA repair roles of the complex. Our results also suggest a structural basis for the opposite effects of the Nse1-3-4 and Nse5-6 subcomplexes in regulating Smc5/6 ATPase activity. Collectively, our integrated structural and functional data provide a framework for understanding Smc5/6 assembly and function.

PubMed: 38890552
DOI: 10.1038/s41594-024-01319-1

Experimental method

ELECTRON MICROSCOPY (6.9 Å)