Molecular determinants of the hanatoxin binding in voltage-gated K+-channel drk1.
The carboxyl terminus of S3 segment (S3(C)) in voltage-gated potassium channels was proposed to bear the binding site for gating modifier toxins like Hanatoxin and a helical secondary structural arrangement was suggested. Due to the lack of complete structure in high resolution for such a channel molecule, no further direct experimental data to elucidate the mechanism for their binding conformations could thus far be derived. In order to examine the putative three-dimensional structure of S3(C) and to illustrate the residues required for Hanatoxin binding, molecular simulation and docking were performed, based on the solution structure of Hanatoxin and the structural information from lysine-scanning results for S3(C) fragment. From our results, it is indicated that both hydrophobic and electrostatic interactions are utilized to stabilize the toxin binding. Detailed docking residues and appropriate orientation for binding regarding hydrophobic/-philic environments are also described. Compared with the functional data proposed by previous studies, the helical structural arrangement for the C-terminus of S3 segment in voltage-gated potassium channels can therefore be further emphasized.
Lou
Kuo-Long
KL
Graduate Institute of Oral Biology, Medical College, National Taiwan University, Taipei, Taiwan. kllou@ntumc.org
Huang
Po-Tsang
PT
Shiau
Yu-Shuan
YS
Shiau
Yuh-Yuan
YY
D001665:Binding Sites; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D046911:Macromolecular Substances; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D015221:Potassium Channels / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D021122:Protein Subunits
D046911:Macromolecular Substances; D010455:Peptides; D015221:Potassium Channels; D021122:Protein Subunits; C096469:hanatoxin