Isolated aquaporin in its closed conformation

Abstract

The invention relates to an isolated aquaporin having a bound ligand, wherein said ligand close the conformation of said aquaporin and inhibit and/or reduce water transport of said aquaporin, and/or a high resolution structure of an isolated aquaporin in a closed conformation characterised by the coordinates deposited at the Protein Data Bank ID:1Z98, a crystal of said isolated aquaporin as well as the coordinates defining said crystal and the use of said aquaporin, and the use of the high-resolution structure as defined by the coordinates deposited at PDB ID:1Z98, and a method to produce said aquaporin.

1 . A method of creating a model of a closed aquaporin of unknown 3-dimensional (3D) structure, the method comprising:
 replacing one or more amino acids of a an atomic structure of a closed aquaporin of known 3D structure, wherein said atomic structure of a closed aquaporin of known 3D structure comprises the atomic coordinates set forth in Appendix 1, with a corresponding amino acid of the closed aquaporin of unknown 3D structure; and   producing a model of the 3D structure of the closed aquaporin of unknown 3D structure.   
     
     
         2 . The method according to  claim 1 , wherein said closed aquaporin of unknown 3D structure is a mammalian aquaporin. 
     
     
         3 . An in-silico method of creating a homology model of a closed aquaporin of unknown structure, the method comprising:
 computationally mutating at least one of the amino acid residues in a high resolution structure of a spinach aquaporin denoted SoPIP2;1 characterized by the atomic coordinates set forth in Appendix 1 into the corresponding amino acid residue of said aquaporin of unknown structure;   producing said homology model of said aquaporin of unknown structure; and   optionally computationally refining said homology model.   
     
     
         4 . The method according to  claim 3 , wherein said closed aquaporin of unknown structure is a mammalian aquaporin. 
     
     
         5 . An in-silico method of creating a homology model of a closed aquaporin of unknown structure, the method comprising:
 computationally mutating at least one of the amino acid residues in a high resolution structure of a crystalline, isolated, closed aquaporin of SEQ ID NO:33, wherein said aquaporin is a spinach aquaporin denoted SoPIP2;1 and comprises a bound cadmium ion; the crystal being in space I4 and having unit cell dimensions a, b, c (Å) 90.0, 90.0, 188.9 and α, β, γ (°) 90.0, 90.0, 90.0, into the corresponding amino acid residue of said aquaporin of unknown structure;   producing said homology model of said aquaporin of unknown structure; and   optionally computationally refining said homology model.   
     
     
         6 . The method according to  claim 4 , wherein said closed aquaporin of SEQ ID NO:33 is a crystal of an aquaporin having a high resolution structure characterized by the atomic coordinates set forth in Appendix 1. 
     
     
         7 . The method according to  claim 4 , wherein said closed aquaporin of unknown structure is a mammalian aquaporin.