title: Yeast rvb1 and rvb2 proteins oligomerize as a conformationally variable dodecamer with low frequency.
abstract: Rvb1 and Rvb2 are conserved AAA+ (ATPases associated with diverse cellular activities) proteins found at the core of large multicomponent complexes that play key roles in chromatin remodeling, integrity of the telomeres, ribonucleoprotein complex biogenesis and other essential cellular processes. These proteins contain an AAA+ domain for ATP binding and hydrolysis and an insertion domain proposed to bind DNA/RNA. Yeast Rvb1 and Rvb2 proteins oligomerize primarily as heterohexameric rings. The six AAA+ core domains form the body of the ring and the insertion domains protrude from one face of the ring. Conversely, human Rvbs form a mixture of hexamers and dodecamers made of two stacked hexamers interacting through the insertion domains. Human dodecamers adopt either a contracted or a stretched conformation. Here, we found that yeast Rvb1/Rvb2 complexes when assembled in vivo mainly form hexamers but they also assemble as dodecamers with a frequency lower than 10%. Yeast dodecamers adopt not only the stretched and contracted structures that have been described for human Rvb1/Rvb2 dodecamers but also intermediate conformations in between these two extreme states. The orientation of the insertion domains of Rvb1 and Rvb2 proteins in these conformers changes as the dodecamer transitions from the stretched structure to a more contracted structure. Finally, we observed that for the yeast proteins, oligomerization as a dodecamer inhibits the ATPase activity of the Rvb1/Rvb2 complex. These results indicate that although human and yeast Rvb1 and Rvb2 proteins share high degree of homology, there are significant differences in their oligomeric behavior and dynamics.
authors: Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.
authors: Ajitha
authors: A
authors: Jeganathan
authors: Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.
authors: Vivian
authors: V
authors: Leong
authors: Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
authors: Liang
authors: L
authors: Zhao
authors: Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
authors: Jennifer
authors: J
authors: Huen
authors: Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
authors: Nardin
authors: N
authors: Nano
authors: Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.
authors: Walid A
authors: WA
authors: Houry
authors: Department of Biochemistry and Biomedical Sciences and Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1. Electronic address: ortegaj@mcmaster.ca.
authors: Joaquin
authors: J
authors: Ortega
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly; D018360:Crystallography, X-Ray; D004265:DNA Helicases / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D008958:Models, Molecular; D011487:Protein Conformation; D055503:Protein Multimerization; D021122:Protein Subunits; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000251:Adenosine Triphosphatases; C428198:RVB1 protein, S cerevisiae; C428199:RVB2 protein, S cerevisiae; D000074183:ATPases Associated with Diverse Cellular Activities; D004265:DNA Helicases; C486549:RUVBL1 protein, human; C122079:RUVBL2 protein, human
keywords: AAA+; chromatin remodeling; electron microscopy; pontin; reptin