Extended Data Fig. 8: Analysis of a positively charged surface near the active site of ApaH.

(a) Multiple sequence alignment for the region corresponding to amino acids 75–88 of E. coli ApaH. The entire protein sequences were aligned well, as evidenced by the absence of gaps and the perfect alignment of the flanking regions, which contain highly conserved residues such as Asn65, His66, Asp67, and Trp101. The figure shows representative sequences with various numbers and distributions of positively charged residues, as well as the absence of these residues in the 75–88 region. (b–e). Effects of the mutations on the hydrolysis of various substrates by E. coli ApaH. Hydrolysis of Ap₄A (b,c), Ap₄AG (c), and Up₄AG (d). Left, full-time course and right, initial rates of hydrolysis, shown with the initial rate constants (k, s⁻¹). The decapping curve for the WT protein is shown as a dashed line. Data points are from two independent experiments (n = 2) with similar results.