%%% --- Biophysics of Macromolecules --- %%%
%%% --- LMU - Sommersemester 2020    --- %%%
%%% --- Prof. Lipfert                --- %%%
%%%
%%% Solutions to 
%%% Problem set 2, Problem 2
%%% Two-state protein folding

clc; clear;

%%% Define thermal energy
RT = 0.6; % Thermal energy in kcal/mol


%%% Plot data for T. Thermophilus PGK
figure(1); clf; hold on; box on;

dG_0 = -4;
m = 2;
xplot = 0:0.1:5;
yplot = (1./(1+exp(-(dG_0 + m.*xplot)./RT)));

plot(xplot, yplot, 'b-', 'linewidth', 2)
set(gca,'LineWidth', 1,'FontSize', 25, 'FontWeight', 'bold', 'TickLength',[0.02 0.02])
ylabel('Fraction unfolded');
xlabel('[GdnHCl] (M)');
axis([-0.2 5.2 -0.1 1.1])

print(figure(1),'-r300','-dpng', 'Two_state_folding.png')