Analysis of proton exchange kinetics with time-dependent exchange rate.
Mass spectrometry is used to probe the kinetics of hydrogen-deuterium exchange in lysozyme in pH 5, 6 and 7.4. An analysis based on a Verhulst growth model is proposed and effectively applied to the kinetics of the hydrogen exchange. The data are described by a power-like function which is based on a time-dependence of the exchange rate. Experimental data ranging over many time scales is considered and accurate fits of a power-like function are obtained. Results of fittings show correlation between faster hydrogen-deuterium exchange and increase of pH. Furthermore a model is presented that discriminates between easily exchangeable hydrogens (located in close proximity to the protein surface) and those protected from the exchange (located in the protein interior). A possible interpretation of the model and its biological significance are discussed.
Rutkowska-Wlodarczyk
Izabela
I
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
Kierdaszuk
Borys
B
Wlodarczyk
Jakub
J
D000818:Animals; D002645:Chickens; D041961:Deuterium Exchange Measurement; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007700:Kinetics; D013058:Mass Spectrometry; D008954:Models, Biological; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D011522:Protons
D011522:Protons; D009113:Muramidase