Thermal stability of Rv0805. A, purified Rv08051–318 and Rv08051–278 proteins (1 μg each) were incubated at 80 °C in assay buffer, in the absence of substrate. At the indicated times, an aliquot was removed and chilled on ice. Assays were performed on all samples at the end of incubation by addition of bis-pNPP as the substrate. B, circular dichroism spectra were collected at 37 °C after incubation of proteins at 80 °C at the indicated times. Control, spectrum at 37 °C with no preincubation at 80 °C.