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CHIP28 geometry is restricted by its intrinsic tryptophan fluorescence properties. Hydropathy analysis shows that three of the four tryptophans in CHIP28 occur in close proximity to membrane-spanning regions. The outer region of the bilayer shows the fourth tryptophan. Selective polar quenchers and those linked by membranes are used to examine tryptophan fluorescence in proteins whose complexities are identical. Tryptophan characteristics, their position and the influence of the agonists on the structure of the protein, are determined by this process.

A group of channel/pore proteins, which includes the lens protein MIP26, reveals the integral membrane protein CHIP28 as a prominent water channel. Circular dichroism and Fourier transform infrared spectroscopy are used to distill the functional, delipidated CHIP28, to homogeneity and to analyze its secondary geometry. Anion-exchange chromatography is used to distill and delipidate CHIP28 in the early stages. Beta-octylglucoside is used to solubilize N-lauroylsarcosine-stripped erythrocyte membranes before anion-exchange chromatography.