3.5.2.17 ? x * 12439, calculated, x * 15000, SDS-PAGE of recombinant protein 711070 3.5.2.17 homotetramer 4 * 13000, SDS-PAGE 688334 3.5.2.17 homotetramer 4 * 14000, SDS-PAGE 733937 3.5.2.17 homotetramer size exclusion chromatography 666761 3.5.2.17 homotetramer x-ray crystallography 688335 3.5.2.17 monomer 1 * 68000, SDS-PAGE 644456 3.5.2.17 tetramer - 697901 3.5.2.17 tetramer 4 * 36600, calculated 711614 3.5.2.17 tetramer structure variations depends on pH value 697901