InterPro domain: IPR029059

The alpha/beta hydrolase fold [ 1 ] is common to a number of hydrolytic enzymes of widely differing phylogenetic origin and catalytic function. The core of each enzyme is an alpha/beta-sheet (rather than a barrel), containing 8 strands connected by helices [ 2 ]. The enzymes are believed to have diverged from a common ancestor, preserving the arrangement of the catalytic residues. All have a catalytic triad, the elements of which are borne on loops, which are the best conserved structural features of the fold. Esterase (EST) from Pseudomonas putida is a member of the alpha/beta hydrolase fold superfamily of enzymes [ 2 ].

In most of the family members the beta-strands are parallels, but some have an inversion of the first strands, which gives it an antiparallel orientation. The catalytic triad residues are presented on loops. One of these is the nucleophile elbow and is the most conserved feature of the fold. Some other members lack one or all of the catalytic residues. Some members are therefore inactive but others are involved in surface recognition. The ESTHER database [ 3 ] gathers and annotates all the published information related to gene and protein sequences of this superfamily [ 4 ].

This entry matches a diverse range of alpha/beta hydrolase enzymes, including a cutinase G9BY57 from unknown prokaryotic organism from soil [ 4 , 5 ].

1. The alpha/beta hydrolase fold. Protein Eng. 5, 197-211
2. Stereoselective esterase from Pseudomonas putida IFO12996 reveals alpha/beta hydrolase folds for D-beta-acetylthioisobutyric acid synthesis. J. Bacteriol. 187, 8470-6
3. ESTHER, the database of the alpha/beta-hydrolase fold superfamily of proteins. Nucleic Acids Res. 32, D145-7
4. Isolation of a novel cutinase homolog with polyethylene terephthalate-degrading activity from leaf-branch compost by using a metagenomic approach. Appl. Environ. Microbiol. 78, 1556-62
5. An engineered PET depolymerase to break down and recycle plastic bottles. Nature 580, 216-219