Presentation on theme: "Adsorption and Desorption Profiles of MIT on POPA and POPC Membranes Reporter: Guanglin Kuang."— Presentation transcript:
Adsorption and Desorption Profiles of MIT on POPA and POPC Membranes Reporter: Guanglin Kuang
MIT domain Microtubule Interacting and Trafficking domain of the chitin synthase of Saprolegnia monoica. 2
POPC POPA Interaction with membranes 3
Umbrella Sampling Umbrella sampling is a technique used to improve the sampling of a system where ergodicity is hindered by the form of the system's energy landscape. 4
Umbrella Sampling-Theory (1) (3) (4) 5 Biased potential energy in window i: (2) Biasing window potential in window i: The unbiased distribution function in window i: The biased distribution function in window i:
6 (5) (6) (7) Umbrella Sampling-Theory From (3) and (4):Probability
Weighted Histogram Analysis Method (WHAM) (8) (9) (10) (11) (12) 7 The global distribution function is: From (8), (9) and (10): J Comput Phys. 1977, 23: J Comput Chem. 1992, 13(8): Comput Phys Commun. 1995, 91: J. Chem. Theory Comput. 2010, 6: 3713–3720 Wires Comput Mol Sci. 2011, 1:
8 Work Flow: Gromacs 4.6.1, CHARMM27 for protein and lipid Adsorption: 100 ns; COM Pull: 20 ns; Umbrella Sampling : 40x10 ns=400 ns
P1 P2 P3 P4 P5 Different Adsorption Modes of MIT on the POPA Bilayer 9
P1 P2 P3 P4 P5 Different Adsorption Modes of MIT on the POPC Bilayer 10
Adsorption and Desorption Profiles of MIT on POPA and POPC Bilayers POPC POPA 11
POPC POPA Binding Modes of MIT with POPA and POPC 12 POPC Any way to quantify this residue-lipid interaction???
Conclusions The adsorption and desorption profiles of MIT on POPA and POPC are significantly different. Salt-bridges between the arginine residues of MIT and POPA are the reason for the high affinity over POPC. The initial configuration also influences the binding affinity, especially for POPA, where the configuration with the most arginine-phosphate interactions has the highest binding affinity. Other factors, like hydrophobic interaction, electrostatic interaction and steric effect, also influence the binding affinity. ….. 13 Thank you for you attention!