Surface fractality of proteins from theory and NMR data

Different approaches to study protein surface fractality are considered. An approach based on analysis of surface versus molecular weight dependence is shown to be an informative tool for investigation of protein surface behaviour. An evidence for protein surface fractality, obtained with the use of this analysis from the data of both NMR measurements in protein solutions and computer analysis of protein structures, is presented. Obtained value of fractal dimension of protein surface (ds congruent to 2.2) is in a good agreement with the results of conventional approach (with variation of yardstick length) to protein surface fractality. A conclusion is made that surface enlargement due to the rise of protein molecular weight is accompanied by the increase of maximum scale of irregularities on protein surface. Possible effect of surface fractality on hydrodynamic characteristics of protein molecules in solution is discussed.