1 Tipping the Balance of the Protein Kinase PDK1 Allosteric Regulatory Mechanism by Low- Molecular-Weight Ligands Jörg O. Schulze 1 †, Giorgio Saladino 2 †, Katrien Busschots 1 ‡, Sonja Neimanis 1 ‡, Evelyn Süß 1 , Dalibor Odadzic 1 , Stefan Zeuzem 1 , Valerie Hindie 1 ‡, Amanda K. Herbrand 1 , María-Natalia Lisa 3 , Pedro M. Alzari 3 , Francesco L. Gervasio 2,4 * and Ricardo M. Biondi 1,5 * 1 Research Group PhosphoSites, Department of Internal Medicine I, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt; 2 Department of Chemistry, University College London, 20 Gordon Street London WC1H 0AJ, UK; 3 Structural Biochemistry Unit, Pasteur Institute, Rue du Dr. Roux 25, F-75724 Paris, France; 4 Research Department of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK; 5 German Cancer Consortium (DKTK), Heidelberg, Germany; German Cancer Research Center (DKFZ), Heidelberg, Germany. *Corresponding authors: R.M.B. (e-mail: biondi@med.uni-frankfurt.de) and F.L.G. (e-mail: f.l.gervasio@ucl.ac.uk) Jörg O. Schulze and Giorgio Saladino contributed equally to this work Running Title: Bi-directional allostery in PDK1 using small compounds K.B., current address, European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Geel, Belgium. V.H., current address, Hybrigenics services, Paris, France. S.N., current address, Klinik für Kinder- und Jugendmedizin, Universitätsklinikum Frankfurt, Frankfurt, Germany. Manuscript 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65