From metagenome: MCA23DSaliva (human oral metagenome). MG8, from the human saliva metagenome has robust PET plastic degradation activities under different temperature and salinity conditions, outperforming several naturally occurring and engineered hydrolases in degrading PET. By encoding 2,3-diaminopropionic acid (DAP) in place of the catalytic serine of MG8, this non-canonical amino acid was used to covalently trap the acyl-enzyme intermediate of MG8. So this PET-degrading enzyme was converted into a covalent binder of PET. MG8(DAP) covalently captures instead of degrading PET
(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Eukaryota: NE > Cryptophyta: NE > Pyrenomonadales: NE > environmental samples: NE > uncultured Pyrenomonadales: NE
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA MKALTFSKSFLSAIAAGALMLSASAMANNPPPPDDPGAPSPYQRGPDPTV SFVEASRGNYRVATSNVSSLVSGFGGGTIHYPSNATGTMGAIVVIPGYVS GEGSIDWWGPKLASYGFVVMTIGTNSGFDQPPSRARQINNALDYLVEQNT RTGSPVRGMIDPSRLGVIGWSMGGGGTIRVAGEGRIKAAIPLAPWDTSSI PSRGVQAPTLIFACQSDVVAPVRSHASPFYNALPGSISKAFVNLNNGNHF CANGGSSFGRYDAALGRLGVSWMKRFLDEDRRYSQFLCGPNHTGDRQITE YRGNCPY
We report a bioinformatic workflow and subsequent discovery of a new polyethylene terephthalate (PET) hydrolase, which we named MG8, from the human saliva metagenome. MG8 has robust PET plastic degradation activities under different temperature and salinity conditions, outperforming several naturally occurring and engineered hydrolases in degrading PET. Moreover, we genetically encoded 2,3-diaminopropionic acid (DAP) in place of the catalytic serine residue of MG8, thereby converting a PET hydrolase into a covalent binder for bio-functionalization of PET. We show that MG8(DAP), in conjunction with a split green fluorescent protein system, can be used to attach protein cargos to PET as well as other polyester plastics. The discovery of a highly active PET hydrolase from the human metagenome-currently an underexplored resource for industrial enzyme discovery-as well as the repurposing of such an enzyme into a plastic functionalization tool, should facilitate ongoing efforts to degrade and maximize reusability of PET.
