InterPro domain: IPR036514

SGNH hydrolase has a similar fold to flavoproteins, namely a three-layer alpha/beta/alpha structure, where the beta-sheets are composed of five parallel strands. Enzymes containing this domain act as esterases and lipases, but have little sequence homology to true lipases [ 1 , 2 ]. Proteins containing this type of esterase domain have been found in a variety of hydrolases; those with structural information include an esterase from Streptomyces scabies [ 3 ]; the esterase domain of viral haemagglutinin-esterase surface glycoproteins (influenza C virus, coronaviruses and toroviruses) [ 4 ]; mammalian acetylhydrolases [ 5 ]; fungal rhamnogalacturonan acetylesterase [ 6 ]; and the multifunctional enzyme thioesterase I (TAP) from Escherichia coli [ 7 ]. SGNH hydrolase-type esterase domains contain unique hydrogen bond network that stabilises their catalytic centres; they usually contain the catalytic triad Ser/Acid/His [ 8 ].

1. Rhamnogalacturonan acetylesterase elucidates the structure and function of a new family of hydrolases. Structure 8, 373-83
2. GDSL family of serine esterases/lipases. Prog. Lipid Res. 43, 534-52
3. A novel variant of the catalytic triad in the Streptomyces scabies esterase. Nat. Struct. Biol. 2, 218-23
4. Structure of the haemagglutinin-esterase-fusion glycoprotein of influenza C virus. Nature 396, 92-6
5. Preparation and crystal structure of the recombinant alpha(1)/alpha(2) catalytic heterodimer of bovine brain platelet-activating factor acetylhydrolase Ib. Protein Eng. 14, 513-9
6. A branched N-linked glycan at atomic resolution in the 1.12 A structure of rhamnogalacturonan acetylesterase. Acta Crystallogr. D Biol. Crystallogr. 58, 111-9
7. Crystal structure of Escherichia coli thioesterase I/protease I/lysophospholipase L1: consensus sequence blocks constitute the catalytic center of SGNH-hydrolases through a conserved hydrogen bond network. J. Mol. Biol. 330, 539-51
8. Catalytic Dyad in the SGNH Hydrolase Superfamily: In-depth Insight into Structural Parameters Tuning the Catalytic Process of Extracellular Lipase from Streptomyces rimosus. ACS Chem Biol 12, 1928-1936