mainly hydrolytic enzymes and related proteins which carry out various biological functions; MBL-fold metallohydrolase domain
Members of the MBL-fold metallohydrolase superfamily are mainly hydrolytic enzymes which carry out a variety of biological functions. The class B metal beta-lactamases (MBLs) for which this fold was named perform only a small fraction of the activities included in this superfamily. Activities carried out by superfamily members include class B beta-lactamases which can catalyze the hydrolysis of a wide range of beta-lactam antibiotics, hydroxyacylglutathione hydrolases (also called glyoxalase II) which hydrolyze S-d-lactoylglutathione to d-lactate in the second step of the glycoxlase system, AHL lactonases which catalyze the hydrolysis and opening of the homoserine lactone rings of acyl homoserine lactones (AHLs), persulfide dioxygenase which catalyze the oxidation of glutathione persulfide to glutathione and persulfite in the mitochondria, flavodiiron proteins which catalyze the reduction of oxygen and/or nitric oxide to water or nitrous oxide respectively, cleavage and polyadenylation specificity factors such as the Int9 and Int11 subunits of Integrator, Sdsa1-like and AtsA-like arylsulfatases, 5'-exonucleases human SNM1A and yeast Pso2p, ribonuclease J which has both 5'-3' exoribonucleolytic and endonucleolytic activity and ribonuclease Z which catalyzes the endonucleolytic removal of the 3' extension of the majority of tRNA precursors, cyclic nucleotide phosphodiesterases which decompose cyclic adenosine and guanosine 3', 5'-monophosphate (cAMP and cGMP) respectively, insecticide hydrolases, and proteins required for natural transformation competence. The diversity of biological roles is reflected in variations in the active site metallo-chemistry, for example classical members of the superfamily are di-, or less commonly mono-, zinc-ion-dependent hydrolases, human persulfide dioxygenase ETHE1 is a mono-iron binding member of the superfamily; Arabidopsis thaliana hydroxyacylglutathione hydrolases incorporates iron, manganese, and zinc in its dinuclear metal binding site, and flavodiiron proteins contains a diiron site.
Jiyao W et al.(2023). "The conserved domain database in 2023.",