SDS-PAGE analysis of SSO1353. Lane 1, molecular weight markers; lane 2, E. coli BL21(DE3)Ril/pET1353 soluble protein extract (45 μg); lanes 3–5, protein extract after heat treatment at 55, 75, and 85 °C, respectively (70, 120 and 84 μg, respectively); lane 6, typical sample after hydrophobic chromatography (21 μg); lane 7, sample after gel filtration (3 μg).