Figure 3
Active-site conservation in the SGNH hydrolase superfamily. (a) Surface model of Ape1 displaying the active groove for acetate. According to the active-site arrangement, this groove is absolutely conserved in all members of the SGNH hydrolase superfamily. (b) The structure of a putative arylesterase from Agrobacterium tumefaciens (PDB entry 3dci; Midwest Center for Structural Genomics, unpublished work). (c) Platelet-activating factor with bound acetate in the active-site groove (PDB entry 1wab; Ho et al., 1997). (d) Structure of coronavirus haemagglutinin-esterase (PDB entry 3cl5; Zeng et al., 2008). The catalytic serine has to move to create space for the acetate-containing substrate. The entrance of the acetate into the active site ensures the productive conformation of the catalytic triad. A mutation of the catalytic serine to alanine in the coronavirus haemagglutinin-esterase shows a trapped acetate in the active site. (e) Close-up of the active site of coronavirus haemagglutinin-esterase. |