Aquaporin-1 (AQP1) is a homotetrameric water channel abundant in erythrocytes, kidney, and so forth. And erythrocytes change their shapes according to the osmotic pressure of buffer. (see Alberts, B. et al. Molecular Biology of the Cell 4th ed. Garland Science, p601, Lichtman, M.A. et al. eds. Williams Hematology 7th ed. McGraw-Hill Medical 2005, p382, etc.)

So I wish to raise the following three questions:

1. Does AQP1 undergo gating to permeate H2O molecules?

2. If so, can we observe such structural change using AFM in solution?

On cGMP controversy (see, e.g., here and here.):

3. Can we settle the controversy using AFM in solution?

Addendum primum:


A typo corrected.