Nostoc DevT and similar proteins, metallophosphatase domain
DevT (Alr4674) is a putative protein phosphatase from Nostoc PCC 7120 (Anabaena PCC 7120). DevT mutants form mature heterocysts, but they are unable to fix N(2) and must be supplied with a source of combined nitrogen in order to survive. Anabaena DevT shows homology to phosphatases of the PPP family and displays a Mn(2+)-dependent phosphatase activity. DevT is constitutively expressed in both vegetative cells and heterocysts, and is not regulated by NtcA. The heterocyst regulator HetR may exert a certain inhibition on the expression of devT. Under diazotrophic growth conditions, DevT protein accumulates specifically in mature heterocysts. The role that DevT plays in a late essential step of heterocyst differentiation is still unknown. MPPs are functionally diverse, but all share a conserved domain with an active site consisting of two metal ions (usually manganese, iron, or zinc) coordinated with octahedral geometry by a cage of histidine, aspartate, and asparagine residues. The MPP superfamily includes: Mre11/SbcD-like exonucleases, Dbr1-like RNA lariat debranching enzymes, YfcE-like phosphodiesterases, purple acid phosphatases (PAPs), YbbF-like UDP-2,3-diacylglucosamine hydrolases, and acid sphingomyelinases (ASMases). The conserved domain is a double beta-sheet sandwich with a di-metal active site made up of residues located at the C-terminal side of the sheets. This domain is thought to allow for productive metal coordination.
Jiyao W et al.(2023). "The conserved domain database in 2023.",