LYS⁷³⁵ PARITICIPATES ON THE ATP BINDING TO THE ISOLATED C-TERMINUS TRPV1

L. Gryčová, Z Lánský, E. Friedlová, J Teisinger

Institute of Physiology, Academy of Sciences of Czech Republic, 142 00 Praha

Transient receptor potential channel vanilloid receptor 1 (TRPV1) is member of TRP ion channel family. TRPV1 is responsible for a heat and chemical – evocated pain responses and it could be activated by vide range of chemical stimuli. Its activity is modulated by intracellular ATP, by direct interaction with ATP binding domains. Despite missing experimental evidence of the tertiary structure, TRPV1 is predicted to be composed of six transmembrane domains, short hydrophobic stretch that line the pore region and two cellular terminuses.

In this study, we have tested the ability of the Walker A motif located on the isolated C-terminus of TRPV1 to bind ATP. We have identified, using steady state fluorescence experiments and molecular biology tools, single amino acid residues that play crucial role in ATP binding to Walker A domain. We have mutated following amino acids residues for alanine one at a time: P732A, D733A, G734A, K735A, D736A, and D737A. Employing TNP-ATP competition assay and FITC labelling and quenching experiments, we have confirmed the key role of the K735 residue for the binding of the nucleotide. These experimentally obtained data verify the predictions of the molecular homology model of the C-tail of TRPV1.This model has been created using a restraint-based comparative modelling approach, and the value of K_D fits within the experimental error with the value estimated previously (3.3 mM) from electrophysiological experiments (1)

1. Kwak, J., Wang, M. H., Hwang, S. W., Kim, T.-Y., Lee, S.-Y., and Oh, U., Journal of Neuroscience, 20 (2000) 8298 – 8304.

This work was supported by Grant GAAV IAA600110701, GACR 303/07/0915, project (No. H148), Center for Neurosciences No. LC554 MSMT CR, and Research Project No. AVOZ 50110509.