This base-pair substitution causes an amino acid change of arginine to lysine (p.R130L) in the active-site pocket of the phosphatase domain, which is essential for catalysis [ 36].
The phosphatase activity is okadaic acid-resistant, and catalysis requires Mn2+, and not any other cation like Mg2+ or Ca2+[ 22].
The phosphatase activity is okadaic acid-resistant, and catalysis requires Mn2+ but no other cations (Mg2+ or Ca2+).
Upon binding of activators, the catalytic P-loop changes its conformation to allow the catalytic cysteine and arginine residues to be positioned in its proximity as seen in other active PI phosphatases, such as PTEN, leading to active catalysis.
Mutation of specific Cys residues in the putative zinc finger region abolished zinc binding and drastically reduced phosphatase activity, suggesting an allosteric role of zinc in catalysis.
The last arginine residue in the phosphatase active site, which has been shown to be crucial for catalysis [ 58, 59], is replaced by hydrophobic or small polar residues in the plant proteins.
As both residues are important for catalysis [ 15] these 7 sequences are probably inactive phosphatases and were excluded in subsequent analyses.
The Baykov malachite green method (29) was used to establish phosphatase activity with PAP as the substrate and to determine the optimal conditions for catalysis.
Differential catalysis via differential nucleophile activation and leaving group stabilization could contribute to greater phosphatase than sulfatase activity.
The absence of residues directly implicated in catalysis as evidenced by 3D structure imply that these proteins are not phosphatases although the remaining domain is conserved.
