Chain A

1. Chain A Chain D Chain B Chain C Structural Basis of Interaction Between Leginsulin and Basic 7S Globulin (Soybean): Induction of Tyrosine Kinase Activity Chain A Chain D Asp334 Tyr 313 • Amandeep Singh1, Prasoon Thakur2, Megha Meena1, Dhiraj Kumar1, Sonika Bhatnagar1, Ashok K. Dubey1 and • Md. Imtaiyaz Hassan3 12 H-bonds Chain B Chain C Chain A Chain D 1Division of Biotechnology, Netaji Subhas Institute of Technology (University of Delhi) 2Department of Computer Sciences, JamiaMilliaIslamia 3Centre for Interdisciplinary Research in Basic Sciences, JamiaMilliaIslamia Leginsulin Chain B Chain C 6 Salt bridges RESULTS INTRODUCTION In soybean, a protein called Basic 7S Globulin (Bg7S) is believed to be important for cell growth and differentiation control. Bg7S is present in middle lamella of the cell wall and a small hormone like peptide, leginsulin interacts with Bg7S to stimulate its tyrosine kinase activity Well defined docking Hydrophobic forces between leginsulin and Bg7S:chain D play major role PDB: 3AUP RMSD of complex 0.393Ȧ Bg7S: Mol wt. 168kDa Quaternary structure: 4 repeated Units of a 43kDa protomer arranged in a pseudo-222 symmetry PISA Monomer • Major interface: • Chain D, with an interface • area of 491.5Å2 • followed closely by chain A • Chain B interacts the least with interface area of 94.7 Å2 only VEGA ZZ 2.4.0 α-subunit +605.38 kJ/mol -245.3 kJ/mol Minimization Leginsulin HOTSPOTS Kinase Leginsulin binds directly with the α-subunit and stimulates kinase activity in β-subunit of Bg7S SPR spectroscopic Studies β-subunit Experimental data: HOTSPOTS The interacting residues of leginsulin (blue) and Bg7S (chain A: green, chain C: purple and chain D: yellow Alanine scanning mutagenesis Cys15 CONCLUSIONS Pseudo-222 symmetry + structural evidence suggests 2 clefts 3.23 Å With support of experimental evidence, we propose 2 leginsulin molecules bind to Bg7S in its crystal structure state N-terminal region residues 1-45 Cysteine rich region residues 51-95 C-terminal region residues 212-251 Phe31 Ala1 Chain B & Chain C A:Arg233 Chain D & Chain A 2.39 Å D:Phe64 A:Glu358 METHODOLOGY Patchdock: Rigid docking model based on surface complementarity Firedock: Used for refinement 180° rotation VEGA ZZsoftware: Simulation of complex Interface and Hotspot Analysis using online PISAand KFC servers CONCLUSIONS REFERENCES [1] Yamazaki, T., Takaoka, M., Katoh, E., Hanada, K., Sakita, M., Sakata, K., et al. A possible physiological function and the tertiary structure of a 4-kDa peptide in legumes. European journal of biochemistry / FEBS. 2003, 270, 1269-76 [2] Komatsu, S., Koshio, O., and Hirano, H. Protein Kinase Activity and Insulin-binding Activity in Plant Basic 7S Globulin. Bioscience, biotechnology, and biochemistry. 1994, 58, 1705-6. [3] Yoshizawa, T., Shimizu, T., Yamabe, M., Taichi, M., Nishiuchi, Y., Shichijo, N., et al. Crystal structure of basic 7S globulin, a xyloglucan-specific endo-beta-1,4-glucanase inhibitor protein-like protein from soybean lacking inhibitory activity against endo-beta-glucanase. The FEBS journal. 2011, 278, 1944-54. Simulation work done showed the movement of loop containing Tyr 313 However, a mechanism of catalysis by Bg7S is yet to be derived out of prior knowledge and experimental results More work is yet to be done to confirm our initial hypothesis on the catalysis action of the Bg7S