title: Structure and function of a novel type of ATP-dependent Clp protease.
abstract: The Clp protease is conserved among eubacteria and most eukaryotes, and uses ATP to drive protein substrate unfolding and translocation into a chamber of sequestered proteolytic active sites. The main constitutive Clp protease in photosynthetic organisms has evolved into a functionally essential and structurally intricate enzyme. The model Clp protease from the cyanobacterium Synechococcus consists of the HSP100 molecular chaperone ClpC and a mixed proteolytic core comprised of two distinct subunits, ClpP3 and ClpR. We have purified the ClpP3/R complex, the first for a Clp proteolytic core comprised of heterologous subunits. The ClpP3/R complex has unique functional and structural features, consisting of twin heptameric rings each with an identical ClpP3(3)ClpR(4) configuration. As predicted by its lack of an obvious catalytic triad, the ClpR subunit is shown to be proteolytically inactive. Interestingly, extensive modification to ClpR to restore proteolytic activity to this subunit showed that its presence in the core complex is not rate-limiting for the overall proteolytic activity of the ClpCP3/R protease. Altogether, the ClpP3/R complex shows remarkable similarities to the 20 S core of the proteasome, revealing a far greater degree of convergent evolution than previously thought between the development of the Clp protease in photosynthetic organisms and that of the eukaryotic 26 S proteasome.
authors.affiliation: Department of Plant and Environmental Sciences, University of Gothenburg, Box 461, S-405 30 Göteborg, Sweden.
authors.forename: Fredrik I
authors.initials: FI
authors.lastname: Andersson
authors.affiliation: Department of Plant and Environmental Sciences, University of Gothenburg, Box 461, S-405 30 Göteborg, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Tryggvesson
authors.affiliation: Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom.
authors.forename: Michal
authors.initials: M
authors.lastname: Sharon
authors.affiliation: Department of Protein Evolution, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Diemand
authors.affiliation: Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Classen
authors.affiliation: Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Best
authors.affiliation: Zentrum fur Molekulare Biologie der Universität Heidelberg, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
authors.forename: Ronny
authors.initials: R
authors.lastname: Schmidt
authors.affiliation: Department of Applied Microbiology, Lund Institute of Technology, Lund University, Box 124, S-221 00 Lund, Sweden.
authors.forename: Jenny
authors.initials: J
authors.lastname: Schelin
authors.affiliation: Department of Plant and Environmental Sciences, University of Gothenburg, Box 461, S-405 30 Göteborg, Sweden.
authors.forename: Tara M
authors.initials: TM
authors.lastname: Stanne
authors.affiliation: Zentrum fur Molekulare Biologie der Universität Heidelberg, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Bukau
authors.affiliation: Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom.
authors.forename: Carol V
authors.initials: CV
authors.lastname: Robinson
authors.affiliation: Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Witt
authors.affiliation: Zentrum fur Molekulare Biologie der Universität Heidelberg, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Mogk
authors.affiliation: Department of Plant and Environmental Sciences, University of Gothenburg, Box 461, S-405 30 Göteborg, Sweden. Electronic address: adrian.clarke@dpes.gu.se.
authors.forename: Adrian K
authors.initials: AK
authors.lastname: Clarke
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D020134:Catalytic Domain / Q000502:physiology; D049071:Endopeptidase Clp / Q000737:chemistry* / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000737:chemistry / Q000378:metabolism; D020836:Protein Structure, Quaternary / Q000502:physiology; D046940:Synechococcus / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D046912:Multiprotein Complexes; D049071:Endopeptidase Clp; D046988:Proteasome Endopeptidase Complex