FIGURE 8.

The PRO region is an intramolecular inhibitor of AtPME17 enzymatic activity. (a) Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE) analysis of His‐PRO‐AtPME17 expressed in Escherichia coli followed by western blot using anti‐His antibodies. Lane 1, His‐PRO‐AtPME17 form; lane 2, His‐PRO‐AtPME17 after processing by Pichia pastoris specific subtilase (SBT) activity; lane 3, recombinant AtPME17 expressed in P. pastoris; lane 4, P. pastoris culture supernatant with SBT activity cleaned on Sephadex G‐25 PD10 column. MM, molecular mass markers. (b) Western blot using anti‐His antibodies. Lane 1, His‐PRO‐AtPME17 form; lane 2, His‐PRO‐AtPME17 after processing by P. pastoris SBT activity. (c) pectin methylesterase activity revealed by gel diffusion assay in fractions loaded in SDS‐PAGE