[Conformational analysis of protein side chains using two-dimensional Overhauser nuclear effect spectroscopy].

Abstract

The method has been proposed to determine the conformations of protein side-chains (dihedral angles chi 1) using two-dimensional nuclear Overhauser effect spectroscopy data. This method is grounded of the algorithm prepared on the basis of joint consideration of proton-proton distance dependences in dipeptide units of L-amino acid residues on the dihedral angles phi, psi and chi 1 with the accounting of the local sterical conditions of the polypeptide chain. The obtained results gave the possibility to bring the different regions of space (phi, psi) of amino acid residues into the line with the specific sets of nuclear Overhauser effect spectral parameters which unambiguously characterize in most cases the conformational states of their side-chains. The method efficiency was displayed on the test calculation with the utilization as the experimental data of the "model" nuclear Overhauser effect contacts derived from the X-ray atomic coordinates of the bovine pancreatic trypsin inhibitor molecule.