Fig. 3: A unique type of PAP phosphatase.
From: Assimilatory sulfate reduction in the marine methanogen Methanothermococcus thermolithotrophicus
a, Top panel, reaction catalysed by MtPAPP; Bottom panel, specific activity of the MtPAPP determined via the production of Pi (left) and relative enzymatic activity towards different nucleotides (right). Data are presented as mean ± s.d. and individual values are shown as grey spheres (n = 3 replicates). b, Organization of MtPAPP shown in cartoon representation. The N and C termini are highlighted as blue and red balls, respectively. Carbon, nitrogen, oxygen and phosphorus of AMP is coloured as cyan, blue, red and orange, respectively. c, Close-up view of the active site of MtPAPP. The residues coordinating the AMP and Mn2+ ion are highlighted by sticks and coloured as in b, with the residues from the DHH motif coloured in pink. d, Cut-through view of MtPAPP structure shown in surface representation and coloured by its sequence conservation across 168 archaeal homologues. The colour gradient ranges from variable (teal) to conserved (magenta). e, Secondary structure representation was done with ESPript 3.0 (ref. 61). The coloured frame corresponds to the different domains: DHH domain in light green, linker in grey and DHHA1 domain in darker green. Perfectly and well-conserved residues across 168 archaeal homologues are highlighted in red and yellow, respectively. The secondary structures composing MtPAPP are labelled, in which β-sheets, α-helices, and β-turns are highlighted as arrows, springs and bold TT, respectively.
