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-Structure paper
Title | Integrative analysis reveals unique structural and functional features of the Smc5/6 complex. |
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Journal, issue, pages | Proc Natl Acad Sci U S A, Vol. 118, Issue 19, Year 2021 |
Publish date | May 11, 2021 |
![]() | You Yu / Shibai Li / Zheng Ser / Tanmoy Sanyal / Koyi Choi / Bingbing Wan / Huihui Kuang / Andrej Sali / Alex Kentsis / Dinshaw J Patel / Xiaolan Zhao / ![]() |
PubMed Abstract | Structural maintenance of chromosomes (SMC) complexes are critical chromatin modulators. In eukaryotes, the cohesin and condensin SMC complexes organize chromatin, while the Smc5/6 complex directly ...Structural maintenance of chromosomes (SMC) complexes are critical chromatin modulators. In eukaryotes, the cohesin and condensin SMC complexes organize chromatin, while the Smc5/6 complex directly regulates DNA replication and repair. The molecular basis for the distinct functions of Smc5/6 is poorly understood. Here, we report an integrative structural study of the budding yeast Smc5/6 holo-complex using electron microscopy, cross-linking mass spectrometry, and computational modeling. We show that the Smc5/6 complex possesses several unique features, while sharing some architectural characteristics with other SMC complexes. In contrast to arm-folded structures of cohesin and condensin, Smc5 and Smc6 arm regions do not fold back on themselves. Instead, these long filamentous regions interact with subunits uniquely acquired by the Smc5/6 complex, namely the Nse2 SUMO ligase and the Nse5/Nse6 subcomplex, with the latter also serving as a linchpin connecting distal parts of the complex. Our 3.0-Å resolution cryoelectron microscopy structure of the Nse5/Nse6 core further reveals a clasped-hand topology and a dimeric interface important for cell growth. Finally, we provide evidence that Nse5/Nse6 uses its SUMO-binding motifs to contribute to Nse2-mediated sumoylation. Collectively, our integrative study identifies distinct structural features of the Smc5/6 complex and functional cooperation among its coevolved unique subunits. |
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Methods | EM (single particle) |
Resolution | 3.2 Å |
Structure data | EMDB-23517, PDB-7lto: |
Source |
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![]() | STRUCTURAL PROTEIN / SMC5/6 / Nse5-6 / Nse5 / Nse6 / complex / SUMO-binding |