title: A novel family of soluble minimal scaffolds provides structural insight into the catalytic domains of integral membrane metallopeptidases.
abstract: In the search for structural models of integral-membrane metallopeptidases (MPs), we discovered three related proteins from thermophilic prokaryotes, which we grouped into a novel family called "minigluzincins." We determined the crystal structures of the zymogens of two of these (Pyrococcus abyssi proabylysin and Methanocaldococcus jannaschii projannalysin), which are soluble and, with ∼100 residues, constitute the shortest structurally characterized MPs to date. Despite relevant sequence and structural similarity, the structures revealed two unique mechanisms of latency maintenance through the C-terminal segments previously unseen in MPs as follows: intramolecular, through an extended tail, in proabylysin, and crosswise intermolecular, through a helix swap, in projannalysin. In addition, structural and sequence comparisons revealed large similarity with MPs of the gluzincin tribe such as thermolysin, leukotriene A4 hydrolase relatives, and cowrins. Noteworthy, gluzincins mostly contain a glutamate as third characteristic zinc ligand, whereas minigluzincins have a histidine. Sequence and structural similarity further allowed us to ascertain that minigluzincins are very similar to the catalytic domains of integral membrane MPs of the MEROPS database families M48 and M56, such as FACE1, HtpX, Oma1, and BlaR1/MecR1, which are provided with trans-membrane helices flanking or inserted into a minigluzincin-like catalytic domain. In a time where structural biochemistry of integral-membrane proteins in general still faces formidable challenges, the minigluzincin soluble minimal scaffold may contribute to our understanding of the working mechanisms of these membrane MPs and to the design of novel inhibitors through structure-aided rational drug design approaches.
authors.affiliation: From the Proteolysis Laboratory, Department of Structural Biology, Molecular Biology Institute of Barcelona, Consejo Superior de Investigaciones Científicas, c/Baldiri Reixac, 15-21, 08028 Barcelona.
authors.forename: Mar
authors.initials: M
authors.lastname: López-Pelegrín
authors.affiliation: From the Proteolysis Laboratory, Department of Structural Biology, Molecular Biology Institute of Barcelona, Consejo Superior de Investigaciones Científicas, c/Baldiri Reixac, 15-21, 08028 Barcelona.
authors.forename: Núria
authors.initials: N
authors.lastname: Cerdà-Costa
authors.affiliation: the Genome Biology Group, Centre Nacional d'Anàlisi Genòmic, c/Baldiri Reixac, 4, 08028 Barcelona,; the Gene Regulation, Stem Cells and Cancer Program, Center for Genomic Regulation, c/Dr. Aiguader, 88, 08003 Barcelona.
authors.forename: Francisco
authors.initials: F
authors.lastname: Martínez-Jiménez
authors.affiliation: From the Proteolysis Laboratory, Department of Structural Biology, Molecular Biology Institute of Barcelona, Consejo Superior de Investigaciones Científicas, c/Baldiri Reixac, 15-21, 08028 Barcelona.
authors.forename: Anna
authors.initials: A
authors.lastname: Cintas-Pedrola
authors.affiliation: the Molecular Biology Institute of Barcelona, Consejo Superior de Investigaciones Científicas and Institute for Research in Biomedicine, c/Baldiri Reixac, 10-12, 08028 Barcelona, and.
authors.forename: Albert
authors.initials: A
authors.lastname: Canals
authors.affiliation: From the Proteolysis Laboratory, Department of Structural Biology, Molecular Biology Institute of Barcelona, Consejo Superior de Investigaciones Científicas, c/Baldiri Reixac, 15-21, 08028 Barcelona.
authors.forename: Juan R
authors.initials: JR
authors.lastname: Peinado
authors.affiliation: the Genome Biology Group, Centre Nacional d'Anàlisi Genòmic, c/Baldiri Reixac, 4, 08028 Barcelona,; the Gene Regulation, Stem Cells and Cancer Program, Center for Genomic Regulation, c/Dr. Aiguader, 88, 08003 Barcelona.
authors.forename: Marc A
authors.initials: MA
authors.lastname: Marti-Renom
authors.affiliation: the Departamento de Bioquímica y Biología Molecular and Instituto Universitario de Oncología, Universidad de Oviedo, 33006 Oviedo, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: López-Otín
authors.affiliation: From the Proteolysis Laboratory, Department of Structural Biology, Molecular Biology Institute of Barcelona, Consejo Superior de Investigaciones Científicas, c/Baldiri Reixac, 15-21, 08028 Barcelona,. Electronic address: jlacri@ibmb.csic.es.
authors.forename: Joan L
authors.initials: JL
authors.lastname: Arolas
authors.affiliation: From the Proteolysis Laboratory, Department of Structural Biology, Molecular Biology Institute of Barcelona, Consejo Superior de Investigaciones Científicas, c/Baldiri Reixac, 15-21, 08028 Barcelona,. Electronic address: xgrcri@ibmb.csic.es.
authors.forename: F Xavier
authors.initials: FX
authors.lastname: Gomis-Rüth
mesh_terms: D000595:Amino Acid Sequence; D001105:Archaea / Q000201:enzymology*; D019843:Archaeal Proteins / Q000737:chemistry*; D020134:Catalytic Domain; D019295:Computational Biology; D018360:Crystallography, X-Ray; D004789:Enzyme Activation; D057075:Enzyme Assays; D004792:Enzyme Precursors / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry*; D045726:Metalloproteases / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D059748:Proteolysis; D019711:Pyrococcus / Q000201:enzymology; D012995:Solubility; D040681:Structural Homology, Protein
chemical_list: D019843:Archaeal Proteins; D004792:Enzyme Precursors; D008565:Membrane Proteins; D045726:Metalloproteases
keywords: Catalytic Domain; Enzyme Mechanisms; Enzyme Structure; Enzymology; Membrane Enzymes; Metallopeptidase; Metalloprotease; Molecular Model; Molecular Modeling; Zymogen