Modeling of protein spatial structure using tritium planigraphy

The results of protein spatial structure modeling using the tritium planigraphy technique are presented. The knowledge of 3D structure of macromolecules is obligatory for understanding the basic mechanisms of interaction in biological systems and complex technological processes. Known limitations of the X-ray analysis (crystal state) and NMR (molecular weight) make it necessary to seek new approaches to modeling the spatial structure of proteins. Semiempirical tritium planigraphy is one of these approaches. The method is based on bombardment of the object with a beam of hot tritium atoms (E _at ≥ 0.3 eV) and computer simulation. On the example of proteins of different structural classes, we show that this integrated approach can yield a 3D model well consistent with the X-ray data. An important factor is the sequence of searching for contacts between secondary structure elements: the best fit with the native structure is achieved by assembling the elements from the N- to the C-terminus of the polypeptide chain.