Screening of Conditions that Facilitate Crystallization of Oligopeptidase B from Serratia Proteamaculans by Differential Scanning Fluorimetry

摘要

Oligopeptidases B (OpdBs) are two-domain serine peptidases with trypsin-like substrate specificity belonging to the prolyl oligopeptidase family. These enzymes are involved in the pathogenesis of trypanosomiasis, leishmaniasis, other parasitic infections, and in some cases bacterial infections and are potential targets for the development of therapeutic anti-infective agents. Only two three-dimensional structures of enzymes of this class were determined. Both these enzymes were from protozoa, whereas the structures of bacterial OpdBs are unknown. Differential scanning fluorimetry (thermofluor) was used to increase the efficiency of screening of crystallization conditions of OpdB from the bacterium Serratia proteamaculans (PSP). It was found that low-molecular-weight polyamines can stabilize PSP in solution. A crystal of PSP, which was grown by the vapor-diffusion method in the presence of spermine, was used to collect the X-ray diffraction data set to 1.88 angstrom resolution at the synchrotron radiation source in the National Research Centre "Kurchatov Institute."