Center two y-axes

I have created a plot with two different y-axis, since one of the curves goes from 0 to 3000, and the other from -10 to 10. However, the 0 of the left axis (0 to 3000) is aligned with the -10 of the right axis, both at the bottom of the plot. I want to align both 0's. What can I do?

[dpb]

Not much on one axes and keep the dynamic range of the two axes; the data just don't align such that that works out. If the 0:3000 axes origin is moved to the midpoint to match the RH axis location, then ylim() for that axis will be [-3000 3000] effectively halving the dynamic range of that plot.

Sometimes "the data are just what the data are"