To bend bounds form the natural 90 degrees require an energy source to do the work of bending. That is why I think the 105 degrees between the two protons is best thought of a due to the electrostatic repulsion between them - that can do the work of bending 90 to 105 degrees. Although one can define a radius for the proton, I have no idea what you mean by "bump up against each others van der Waals radius." How would that radius be defined? Do you think the 105 degrees is dynamic - increasing when they "bump"?