ZMB Member Peter Bayer

Peter Bayer

Prof. Dr. Peter Bayer

+49 201 183 4677

Fakultät für Biologie
Room S03 S01 A35
Universität Duisburg-Essen
45117 Essen


Strukturelle und Medizinische Biochemie

    Journal articles

  • Killinger, Kerstin; Böhm, Miriam; Steinbach, Philine; Hagemann, Götz; Blüggel, Mike; Jänen, Karolin; Hohoff, Simone; Bayer, Peter; Herzog, Franz; Westermann, Stefan
    Auto-inhibition of Mif2/CENP-C ensures centromere-dependent kinetochore assembly in budding yeast
    In: The EMBO Journal (2020) pp. e102938
    ISSN: 1460-2075; 0261-4189
  • Vallet, Cecilia; Aschmann, Dennis; Beuck, Christine; Killa, Matthias; Meiners, Annika; Mertel, Marcel; Ehlers, Martin; Bayer, Peter; Schmuck, Carsten; Giese, Michael R. A.; Knauer, Shirley
    Functional Disruption of the Cancer-Relevant Interaction between Survivin and Histone H3 with a Guanidiniocarbonyl Pyrrole Ligand
    In: Angewandte Chemie International Edition Vol. 59 (2020) Nr. 14, pp. 5567 - 5571
    ISSN: 1521-3773; 1433-7851; 0570-0833
  • Göhring, Anna; Michin, Irina; Gerdes, Tina; Schulze, Nina; Blüggel, Mike; Rehic, Edisa; Kaschani, Farnusch; Kaiser, Markus; Bayer, Peter
    Targeting of parvulin interactors by diazirine mediated cross-linking discloses a cellular role of human Par14/17 in actin polymerization
    In: Biological Chemistry (2020)
    ISSN: 1437-4315; 1431-6730
  • Born, Alexandra; Nichols, Parker J.; Henen, Morkos A.; Chi, Celestine N.; Strotz, Dean; Bayer, Peter; Tate, Shin-Ichi; Peng, Jeffrey W.; Vögeli, Beat
    Backbone and side-chain chemical shift assignments of full-length, apo, human Pin1, a phosphoprotein regulator with interdomain allostery
    In: Biomolecular NMR Assignments Vol. 13 (2019) Nr. 1, pp. 85 - 89
    ISSN: 1874-270X; 1874-2718
  • van der Meer, Selina; Loza, Kateryna; Wey, Karolin; Heggen, Marc; Beuck, Christine; Bayer, Peter; Epple, Matthias
    Click chemistry on the surface of ultrasmall gold nanoparticles (2 nm) for covalent ligand attachment followed by nmr spectroscopy
    In: Langmuir Vol. 35 (2019) Nr. 22, pp. 7191 - 7204
    ISSN: 0743-7463; 1520-5827
  • Bartsch, Lina; Bartel, Maria; Gigante, Alba; Iglesias-Fernández, Javier; Ruiz-Blanco, Yasser B.; Beuck, Christine; Briels, Jeroen; Tötsch, Niklas; Bayer, Peter; Sanchez-Garcia, Elsa; Ottmann, Christian; Schmuck, Carsten
    Multivalent Ligands with Tailor-Made Anion Binding Motif as Stabilizers of Protein–Protein Interactions
    In: ChemBioChem Vol. 20 (2019) Nr. 23, pp. 2921 - 2926
    ISSN: 1439-7633; 1439-4227
  • Ruks, Tatjana; Beuck, Christine; Schaller, Torsten; Niemeyer, Felix; Zähres, Manfred; Loza, Kateryna; Heggen, Marc; Hagemann, Ulrich; Mayer, Christian; Bayer, Peter; Epple, Matthias
    Solution NMR Spectroscopy with Isotope-Labeled Cysteine (¹³C and ¹⁵N) Reveals the Surface Structure of l -Cysteine-Coated Ultrasmall Gold Nanoparticles (1.8 nm)
    In: Langmuir Vol. 35 (2019) Nr. 3, pp. 767 - 778
    ISSN: 0743-7463; 1520-5827
  • Rehic, Edisa; Hönig, Dana; Kamba, Bianca; Göhring, Anna; Hofmann, Eckhard; Gasper, Raphael; Matena, Anja; Bayer, Peter
    Structural Analysis of the 42 kDa Parvulin of Trypanosoma brucei
    In: Biomolecules Vol. 9 (2019) Nr. 3, pp. 93
    ISSN: 2218-273X
  • Blüggel, Mike; van den Boom, Johannes; Meyer, Hemmo; Bayer, Peter; Beuck, Christine
    Structure of the PUB Domain from Ubiquitin Regulatory X Domain Protein 1 (UBXD1) and Its Interaction with the p97 AAA+ ATPase
    In: Biomolecules Vol. 9 (2019) Nr. 12, pp. 876
    ISSN: 2218-273X
  • Trusch, Franziska; Loebach, Lars; Wawra, Stephan; Durward, Elaine; Wuensch, Andreas; Iberahim, Nurul Aqilah; De Bruijn, Irene; MacKenzie, Kevin; Willems, Ariane; Toloczko, Aleksandra; Diéguez-Uribeondo, Javier; Rasmussen, Tim; Schrader, Thomas; Bayer, Peter; Secombes, Chris J.; Van West, Pieter
    Cell entry of a host-targeting protein of oomycetes requires gp96
    In: Nature Communications Vol. 9 (2018) Nr. 1, pp. 2347
    ISSN: 2041-1723
  • Matena, Anja; Rehic, Edisa; Hönig, Dana; Kamba, Bianca; Bayer, Peter
    Structure and function of the human parvulins Pin1 and Par14/17
    In: Biological Chemistry Vol. 399 (2018) Nr. 2, pp. 101 - 125
    ISSN: 1437-4315; 1431-6730
  • Wawra, Stephan; Trusch, Franziska; Matena, Anja; Apostolakis, Kostis; Linne, Uwe; Zhukov, Igor; Stanek, Jan; Koźmiński, Wiktor; Davidson, Ian; Secombes, Chris J.; Bayer, Peter; van West, Pieter
    The RxLR motif of the host targeting effector AVR3a of phytophthora infestans is cleaved before secretion
    In: The Plant Cell Vol. 29 (2017) Nr. 6, pp. 1184 - 1195
    ISSN: 1532-298X; 1040-4651
  • Hartmann-Fatu, Cristina; Bayer, Peter
    Determinants of tyrosylprotein sulfation coding and substrate specificity of tyrosylprotein sulfotransferases in metazoans
    In: Chemico-Biological Interactions Vol. 259 (2016) Nr. Part A, pp. 17 - 22
    ISSN: 0009-2797; 1872-7786
  • Trusch, Franziska; Kowski, Klaus; Bravo-Rodriguez, Kenny; Beuck, Christine; Sowislok, Andrea; Wettig, Burkhard; Matena, Anja; Sanchez-Garcia, Elsa; Meyer, Hemmo; Schrader, Thomas; Bayer, Peter
    Molecular tweezers target a protein-protein interface and thereby modulate complex formation
    In: Chemical Communications: ChemComm Vol. 52 (2016) Nr. 98, pp. 14141 - 14144
    ISSN: 1364-548X; 0009-241X; 0022-4936; 1359-7345
  • Hoppstock, Lukas; Trusch, Franziska; Lederer, Christoph; van West, Pieter; Koenneke, Martin; Bayer, Peter
    NmPin from the marine thaumarchaeote Nitrosopumilus maritimus is an active membrane associated prolyl isomerase
    In: BMC Biology (incorporating Journal of Biology) Vol. 14 (2016) Nr. 1, pp. 53
    ISSN: 1741-7007
  • van den Boom, Johannes; Trusch, Franziska; Hoppstock, Lukas; Beuck, Christine; Bayer, Peter
    Structural Characterization of the Loop at the Alpha-Subunit C-Terminus of the Mixed Lineage Leukemia Protein Activating Protease Taspase1
    In: PLoS One Vol. 11 (2016) Nr. 3, pp. e0151431
    ISSN: 1932-6203
  • Hartmann-Fatu, Cristina; Trusch, Franziska; Moll, Carina; Michin, Irina; Hassinen, Antti; Kellokumpu, Sakari; Bayer, Peter
    Heterodimers of Tyrosylprotein Sulfotransferases Suggest Existence of a Higher Organization Level of Transferases in the Membrane of the trans-Golgi Apparatus
    In: Journal of Molecular Biology (JMB) Vol. 427 (2015) Nr. Issue 6, Part B, pp. 1404 - 1412
    ISSN: 0022-2836
  • Saningong, Akuma D.; Bayer, Peter
    Human DNA-binding peptidyl-prolyl cis/trans isomerase Par14 is cell cycle dependently expressed and associates with chromatin in vivo
    In: BMC Biochemistry Vol. 16 (2015) Nr. 1,
    ISSN: 1471-2091
  • Roy Choudhury, Amrita; Sikorska, Emilia; van den Boom, Johannes; Bayer, Peter; Popenda, Lukasz; Szutkowski, Kosma; Jurga, Stefan; Bonomi, Massimiliano; Sali, Andrej; Zhukov, Igor; Passamonti, Sabina; Novič, Marjana
    Structural model of the bilitranslocase transmembrane domain supported by NMR and FRET data
    In: PLoS One Vol. 10 (2015) Nr. 8, pp. e0135455
    ISSN: 1932-6203
  • Trusch, Franziska; Matena, Anja; Vuk, Maja; Körver, Lisa; Knævelsrud, Helene; Freemont, Paul S.; Meyer, Hemmo; Bayer, Peter
    The N-terminal region of the ubiquitin regulatory X (UBX) domain-containing protein 1 (UBXD1) modulates interdomain communication within the valosin-containing protein p97
    In: Journal of Biological Chemistry Vol. 290 (2015) Nr. 49, pp. 29414 - 29427
    ISSN: 0021-9258; 1083-351X
  • van den Boom, Johannes; Mamic, Marija; Baccelliere, Daniele; Zweerink, Susanne; Kaschani, Farnusch; Knauer, Shirley; Bayer, Peter; Kaiser, Markus
    Peptidyl succinimidyl peptides as taspase 1 inhibitors
    In: ChemBioChem Vol. 15 (2014) Nr. 15, pp. 2233 - 2237
    ISSN: 1439-4227; 1439-7633
  • Grum, Daniel; Franke, Stefan; Kraff, Oliver; Heider, Dominik; Schramm, Alexander; Hoffmann, Daniel; Bayer, Peter
    Design of a Modular Protein-Based MRI Contrast Agent for Targeted Application
    In: PLoS One Vol. 8 (2013) Nr. 6, pp. e65346
    ISSN: 1932-6203
  • Elfaki, Imadeldin; Knitsch, Andre; Matena, Anja; Bayer, Peter
    Identification and characterization of peptides that bind the PPIase domain of Parvulin17
    In: Journal of Peptide Science Vol. 19 (2013) Nr. 6, pp. 362 - 369
    ISSN: 1099-1387; 1075-2617
  • Matena, Anja; Sinnen, Christian; van den Boom, Johannes; Wilms, Christoph; Dybowski, Jan Nikolaj; Maltaner, Ricarda; Müller, Jonathan W.; Link, Nina M.; Hoffmann, Daniel; Bayer, Peter
    Transient domain interactions enhance the affinity of the mitotic regulator pin1 toward phosphorylated peptide ligands
    In: Structure Vol. 21 (2013) Nr. 10, pp. 1769 - 1777
    ISSN: 1878-4186
  • Schröder, Elisabeth; Gebel, Lena; Eremeev, Andrey A.; Morgner, Jessica; Grum, Daniel; Knauer, Shirley; Bayer, Peter; Müller, Jonathan W.
    Document Human PAPS synthase isoforms are dynamically regulated enzymes with access to nucleus and cytoplasm
    In: PLoS One Vol. 7 (2012) Nr. 1, pp. e29559
    ISSN: 1932-6203
  • Wawra, Stephan; Bain, Judith; Durward, Elaine; De Bruijn, Irene; Minor, Kirsty L.; Matena, Anja; Löbach, Lars; Whisson, Stephen C.; Bayer, Peter; Porter, Andrew J.; Birch, Paul R. J.; Secombes, Chris J.; Van West, Pieter
    Host-targeting protein 1 (SpHtp1) from the oomycete Saprolegnia parasitica translocates specifically into fish cells in a tyrosine-O-sulphate-dependent manner
    In: Proceedings of the National Academy of Sciences of the United States of America (PNAS) Vol. 109 (2012) Nr. 6, pp. 2096 - 2101
    ISSN: 1091-6490; 0027-8424
  • Hoeppner, Astrid; Thomas, Frank; Rueppel, Alma; Hensel, Reinhard; Blankenfeldt, Wulf; Bayer, Peter; Faust, Annette
    Structure of the corrinoid : coenzyme M methyltransferase MtaA from Methanosarcina mazei
    In: Acta Crystallographica Section D: Biological Crystallography Vol. 68 (2012) Nr. 11, pp. 1549 - 1557
    ISSN: 0907-4449; 1399-0047
  • Elfaki, Imadeldin; Bayer, Peter; Müller, Jonathan W.
    A potential transcriptional regulator is out-of-frame translated from the metallothionein 2A messenger RNA
    In: Analytical Biochemistry Vol. 409 (2011) Nr. 1, pp. 159 - 161
    ISSN: 0003-2697; 1096-0309
  • Müller, Jonathan W.; Link, Nina C; Matena, Anja; Hoppstock, Lukas; Rüppel, Alma; Bayer, Peter; Blankenfeldt, Wulf
    Crystallographic Proof for an Extended Hydrogen Bonding Network in Small Prolyl Isomerases
    In: Journal of the American Chemical Society Vol. 133 (2011) Nr. 50, pp. 20096 - 20099
    ISSN: 0002-7863; 1520-5126
  • Lederer, Christoph; Heider, Dominik; van den Boom, Johannes; Hoffmann, Daniel; Müller, Jonathan W.; Bayer, Peter
    Single-Domain Parvulins Constitute a Specific Marker for Recently Proposed Deep-Branching Archaeal Subgroups
    In: Evolutionary Bioinformatics Vol. 7 (2011) pp. 135 - 148
    ISSN: 1176-9343
  • Jaremko, Lukasz; Jaremko, Mariusz; Elfaki, Imadeldin; Müller, Jonathan W.; Ejchart, Andrzej; Bayer, Peter; Zhukov, Igor
    Structure and Dynamics of the First Archaeal Parvulin Reveal a New Functionally Important Loop in Parvulin-type Prolyl Isomerases
    In: Journal of Biological Chemistry Vol. 286 (2011) pp. 6554 - 6565
    ISSN: 0021-9258; 1083-351X
  • Link, Nina M.; Hunke, Cornelia; Müller, Jonathan W.; Eichler, Jutta; Bayer, Peter
    The solution structure of pGolemi, a high affinity Mena EVH1 binding miniature protein, suggests explanations for paralog-specific binding to Ena/VASP homology (EVH) 1 domains
    In: Biological Chemistry Vol. 390 (2009) Nr. 5-6, pp. 417 - 426
    ISSN: 1437-4315
  • Müller, Jonathan W.; Bayer, Peter
    Small family with key contacts : par14 and par17 parvulin proteins, relatives of pin1, now emerge in biomedical research
    In: Perspectives in Medicinal Chemistry Vol. 2 (2008) pp. 11 - 20
    ISSN: 1177-391X
  • Zhukov, Igor; Bayer, Peter; Schölermann, Beate; Ejchart, Andrzej
    15N magnetic relaxation study of backbone dynamics of the ribosomeassociated cold shock response protein Yfia of Escherichia coli
    In: Acta Biochimica Polonica Vol. 54 (2007) Nr. 4, pp. 769 - 775
    ISSN: 1734-154X; 0001-527X
  • Kessler, Daniel; Papatheodorou, Panagiotis; Stratmann, Tina; Dian, Elke Andrea; Hartmann-Fatu, Cristina; Rassow, Joachim; Bayer, Peter; Müller, Jonathan W.
    The DNA binding parvulin Par17 is targeted to the mitochondrial matrix by a recently evolved prepeptide uniquely present in Hominidae.
    In: BMC Biology (incorporating Journal of Biology) Vol. 5 (2007) pp. 37
    ISSN: 1741-7007
  • Mueller, J.W.; Kessler, D.; Neumann, D.; Stratmann, T.; Papatheodorou, P.; Hartmann-Fatu, C.; Bayer, Peter
    Characterization of novel elongated Parvulin isoforms that are ubiquitously expressed in human tissues and originate from alternative transcription initiation.
    In: BMC Molecular Biology Vol. 7 (2006) pp. 9
    ISSN: 1471-2199
  • Harjes, E.; Harjes, S.; Wohlgemuth, S.; Mueller, K.H.; Krieger, E.; Herrmann, C.; Bayer, Peter
    GTP-Ras disrupts the intramolecular complex of C1 and RA domains of Nore1.
    In: Structure Vol. 14 (2006) pp. 881 - 888
  • Goettsch, S.; Badea, R.A.; Schoelermann, B.; Wotzlaw, C.; Schulz, L.; Müller, J.W.; Rabiller, M.; Bayer, Peter; Hartmann-Fatu, C.
    Golgi targeting and dimerisation of human TPST1, an enzyme with two N-linked carbohydrates, is triggered by its N-terminal transmembrane domain.
    In: (J.Mol.Biol.) Vol. 361 (2006) pp. 436 - 449
  • Goettsch, S.; Badea, R.A.; Müller, J.W.; Schoelermann, B.; Wotzlaw, C.; Schulz, L.; Rabiller, M.; Bayer, Peter; Hartmann-Fatu, C.
    Human TPST1 Transmembrane Domain Triggers Enzyme Dimerisation and Localisation to the Golgi Compartment.
    In: (J Mol Biol.) Vol. 361 (2006) Nr. 3, pp. 436 - 449
  • Niculae, A.; Gruen, M.; Bayer, Peter; Breitling, R.; Alexandrov, K.
    Isotopic labelling of recombinant proteins expressed in the protozoan host Leishmania tarentolae.
    In: Protein Expression & Purification Vol. 48 (2006) pp. 167 - 172
  • Hecker, C.M.; Rabiller, M.; Haglund, K.; Bayer, Peter; Dikic, I.
    Specification of SUMO1 and SUMO2 interacting motifs.
    In: J. Biol. Chem. Vol. 281 (2006) pp. 16117 - 16127
  • Bayer, E.; Thutewohl, M.; Christner, C.; Waldmann, H.; Bayer, Peter
    Identification of hPin1 inhibitors that induce apoptosis in a mammalian Ras transformed cell line
    In: Chemical Communications: ChemComm Vol. 4 (2005) pp. 516 - 518
    ISSN: 1364-548X; 0009-241X; 0022-4936; 1359-7345
  • Harjes, S.; Bayer, Peter; Scheidig, A.
    The Crystal Structure of Human PAPS Synthetase1 Reveals Asymmetry in Substrate Binding.
    In: (J.Mol.Biol.) Vol. 347 (2005) pp. 623 - 635
  • Harjes, S.; Scheidig, A.; Bayer, Peter
    Expression, purification and crystallisation of the human 3?phosphoadenosine-5?phosphosulfate synthetase 1.
    In: (Acta Cryst. D) Vol. 60 (2004) pp. 350 - 352
  • Rabiller, M.; Bayer, Peter
    Protein Structure. D.I. Chasman (ed). Book Review.
    In: (ChemBioChem) Vol. 5 (2004) pp. 547 - 548
  • Blankenfeldt, W.; Kuzin, A.P.; Skarina, T.; Tong, L.; Bayer, Peter; Janning, P.; Thomashow, L.S.; Mavrodi, D.V.
    Structure and function of phenazine-biosynthesis protein PhzF from Pseudomonas fluorescens 2-79.
    In: (PNAS) Vol. 101 (2004) pp. 16431 - 16436
  • Bayer, Peter
    Die Vorliebe für Physik und die Strukturbiologie.
    In: (Nachr.Chemie) Vol. 9 (2003) pp. 917
  • Reimer, Tatiana; Weiwad, Matthias; Schierhorn, Angelika; Ruecknagel, Peter-Karl; Rahfeld, Jens-Ulrich; Bayer, Peter; Fischer, Gunter
    Phosphorylation of the N-terminal domain regulates subcellular localization and DNA binding properties of the peptidyl-prolyl cis/trans isomerase hPar14
    In: Journal of Molecular Biology Vol. 330 (2003) Nr. 5, pp. 955 - 966
    ISSN: 1089-8638
  • Bayer, E.; Goettsch, S.; Müller, J.W.; Griewel, B.; Guiberman, E.; Mayr, L.M.; Bayer, Peter
    Structural analysis of the mitotic regulator hPin1 in solution: insights into domain architecture and substrate binding.
    In: (J Biol Chem.) Vol. 278 (2003) Nr. 28, pp. 26183 - 26193
  • Kalinin, A.; Rak, A.; Shcherbakov, D.; Bayer, Peter
    1H, 13C and 15N resonance assignments of the ribosome-associated cold shock response protein Yfia of Escherichia coli.
    In: (J.Biomol.NMR) Vol. 23 (2002) pp. 335 - 336
  • Goettsch, S.; Goettsch, W.; Morawietz, H.; Bayer, Peter
    Induction of tyrosylprotein sulfotransferase isoform shift in human endothelial cells.
    In: CIRCULATION Vol. 106 (2002) Nr. Suppl., pp. 1444
  • Rabiller, M.; Bayer, Peter
    Molecular Handshake.
    In: (TIBS) Vol. 27 (2002) pp. 502 - 503
  • Goettsch, S; Goettsch, W; Morawietz, H; Bayer, Peter
    Shear stress mediates tyrosylprotein sulfotransferase isoform shift in human endothelial cells.
    In: (Biochem Biophys Res Commun.) Vol. 294 (2002) Nr. 14, pp. 541 - 546
  • Rak, A.; Kalinin, K.; Shcherbakov, D.; Bayer, Peter
    Solution structure of the ribosome-associated cold shock response protein Yfia of Escherichia Coli.
    In: (Biochem Biophys Res Commun) Vol. 299 (2002) pp. 710 - 714
  • Goettsch, S.; Bayer, Peter
    Structural attributes in the conjugation of Ubiquitin, RUB and SUMO to protein substrates.
    In: Frontiers in Bioscience Vol. 7 (2002) pp. 148 - 162
  • Surmacz, Tatiana Anna; Bayer, Elena; Rahfeld, Jens-Ulrich; Fischer, Gunter; Bayer, Peter
    The N-terminal basic domain of human parvulin h Par14 is responsible for the entry to the nucleus and high-affinity DNA-binding
    In: Journal of Molecular Biology (JMB) Vol. 321 (2002) Nr. 2, pp. 235 - 247
    ISSN: 1089-8638
  • Bayer, Peter; Goettsch, S.
    ATP, a trigger for pain-signaling.
    In: (TiBS) Vol. 26 (2001) pp. 12
  • Bayer, Peter; Sekerina, E.
    Delta: a mitogenic regulator of human hematopoesis.
    In: (TiBS) Vol. 26 (2001) pp. 281
  • Kipping, M.; Zarnt, T.; Kiessig, S.; Reimer, U.; Fischer, G.; Bayer, Peter
    Increased backbone flexibility in threonine
    In: Biochemistry Vol. 40 (2001) Nr. 27, pp. 7957 - 7963
    ISSN: 1520-4995; 0006-2960
  • Surmacz, T.; Bayer, Peter
    Living in the cytosol.
    In: (TIBS) Vol. 26 (2001) pp. 703
  • Kohlbacher, O.; Burchardt, A.; Moll, A.; Hildebrandt, A.; Bayer, Peter; Lenhof, H.P.
    Structure prediction of protein complexes by a NMR-based protein docking algorithm.
    In: (J. Biomol. NMR) Vol. 20 (2001) pp. 15 - 21
  • Bayer, Peter; Harjes, S.
    TonB, a mediator of iron uptake in bacteria.
    In: (TIBS) Vol. 26 (2001) pp. 473
  • Sekerina, E; Rahfeld, J U; Müller, J; Fanghänel, J; Rascher, C; Fischer, G; Bayer, Peter
    NMR solution structure of hPar14 reveals similarity to the peptidyl prolyl cis/trans isomerase domain of the mitotic regulator hPin1 but indicates a different functionality of the protein
    In: Journal of Molecular Biology (JMB) Vol. 301 (2000) Nr. 4, pp. 1003 - 1017
    ISSN: 1089-8638; 0022-2836
  • Marx, U.C.; Adermann, K.; Bayer, Peter; Forssmann, W.g.; Rösch, P.
    Solution structures of human parathyroid hormone fragments hPTH(1-34) and hPTH(1-39) and bovine parathyroid hormone fragment bPTH(1-37).
    In: (BBRC) Vol. 267 (2000) pp. 213 - 220

ZMB Research Programme

Professor Peter Bayer participates in the ZMB research programme III, Molecular and Chemical Cell Biology.