MECHANISMS OF GATING AND SELECTIVITY OF AQUAPORINS

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Aquaporins (AQPs) (URL: http://www.ks.uiuc.edu/Research/aquaporins/) are a family of membrane channels specializing in rapid water conduction across biological membranes [1, 2]. They are widely distributed in all forms of life. Impaired functions of AQPs have been directly linked to diseases such as cataracts and diabetes insipidus [3, 4, 5, 6]. Aquaporins form tetramers in the membrane, with each of the four monomers functioning as an independent water pore. A fifth pore is formed in the middle of the tetramer, known as the central pore. MD simulations of membrane-embedded, fully hydrated models of various AQPs with NAMD [7] have revealed the role of the central pore in gas and ion conduction [8, 9]. A proper description of these proteins in their natural environment of lipid and water requires system sizes of 100,000 atoms or more, and simulation times on the order of tens of nanoseconds.