A line that passes through the original has the equation y= a*x
Did you try using fittype and fit?
x=[-5 -4 -3 -2 -1 0 1 2 3 4 5 ];
y=[-478.4 -377.2 -278.6 -180.8 -84.5 0 85.25 181 278.2 377.5 479.2];
FITFUN = fittype('a*x')
FT = fit(x(:), y(:), FITFUN)
fittedY = FT([-6 6])
plot(x, y, 'bo', [-6 6], fittedY, 'rs-')
