Architecture of the Smc5/6 Complex of Saccharomyces cerevisiae Reveals a Unique Interaction between the Nse5-6 Subcomplex and the Hinge Regions of Smc5 and Smc6.
The evolutionarily conserved structural maintenance of chromosome (SMC) proteins forms the core structures of three multisubunit complexes as follows: cohesin, condensin, and the Smc5/6 complex. These complexes play crucial roles in different aspects of chromosomal organization, duplication, and segregation. Although the architectures of cohesin and condensin are better understood, that of the more recently identified Smc5/6 complex remains to be elucidated. We have previously shown that the Smc5/6 complex of Saccharomyces cerevisiae contains Smc5, Smc6, and six non-SMC elements (Nse1-6). In this study, we investigated the architecture of the budding yeast Smc5/6 complex employing the yeast two-hybrid assay as well as in vitro biochemical approaches using purified recombinant proteins. These analyses revealed that Smc5 and Smc6 associate with each other at their hinge regions and constitute the backbone of the complex, whereas the Nse1-6 subunits form three distinct subcomplexes/entities that interact with different regions of Smc5 and Smc6. The Nse1, -3, and -4 subunits form a stable subcomplex that binds to the head and the adjacent coiled-coil region of Smc5. Nse2 binds to the middle of the coiled-coil region of Smc5. Nse5 and Nse6 interact with each other and, as a heterodimer, bind to the hinge regions of Smc5 and Smc6. These findings provide new insights into the structures of the Smc5/6 complex and lay the foundation for further investigations into the mechanism of its functions.
Duan
Xinyuan
X
Brown Cancer Center, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA.
Yang
Yan
Y
Chen
Yu-Hung
YH
Arenz
Jacqueline
J
Rangi
Gurdish K
GK
Zhao
Xiaolan
X
Ye
Hong
H
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D015825:Chromosomes, Fungal / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D020836:Protein Structure, Quaternary / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D000097722:Cohesins
D000251:Adenosine Triphosphatases; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D046912:Multiprotein Complexes; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D000097722:Cohesins; C460369:NSE1 protein, S cerevisiae; C501992:NSE4 protein, S cerevisiae; C575002:NSE5 protein, S cerevisiae; C486627:SMC5 protein, S cerevisiae; C486631:SMC6 protein, S cerevisiae; C108312:condensin complexes