Research :: Case Studies

Crystal Structure of Aquaporins

The four different aquaporin structures determined in the Stroud laboratory (GlpF, AqpZ, Aqp0, AqpM) are illustrated above. Crystallization is a gold standard for ability to clone, express, and adequately purify membrane proteins in a structurally homogeneous form. This therefore establishes that purification of these membrane proteins in structurally homogeneous form has been achieved by procedures used in the Stroud group.

One aquaporin, Aqp0 is eukaryotic, and determined to 2.2Å resolution (Stroud-not yet published), proving, as the other 5 eukaryotic membrane protein structures determined elsewhere do, that there is nothing especially difficult about obtaining well behaved expression of higher animal membrane proteins. The relatively high homology of the 11 human Aquaporins (20-30% identity) (21) to their bacterial orthologs AqpZ and GlpF whose structure we solved suggests that we may be able to express these human eukaryotic proteins in bacteria.

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Crystal Structure of Ammonia Channel

The top view of the monomeric AmtB is shown above. Each channel momomer is shown in a different color. The atomic structure of AmtB is the highest resolution of any membrane protein as we enter the year 2005. This is due to the procedures in use at the MPEC.

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