(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Bacteria: NE > FCB group: NE > Bacteroidetes/Chlorobi group: NE > Bacteroidetes: NE > Flavobacteriia: NE > Flavobacteriales: NE > Flavobacteriaceae: NE > Aequorivita: NE > unclassified Aequorivita: NE > Aequorivita sp. CIP111184: 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 MKKIYAVALFFLATSFAPNIIFAQCGDVTIESLTNPGPYEVATLTEADGL RNGPDYQGATVYYPTNATPPFASIAIVPGFTALPSSVEEWGPFYASHGIV TIIIGTNSLFDFPEERAVALIDALETMRQENTRSSSPLENQLDVDKFAVS GWSMGGGGAQRAAVLDNTIKGVVALCPWLPNASLNHDSPVLIFSGENDPT APPAQHADLHYAATPNTTNKLLFEIENGNHSVANTPNGGNGAVGKIALSW LKLYVDENDCYCPLLTESLLVDPPAASKVLSSFECELLSVPDNSFAISV
Certain members of the Actinobacteria and Proteobacteria are known to degrade polyethylene terephthalate (PET). Here, we describe the first functional PET-active enzymes from the Bacteroidetes phylum. Using a PETase-specific Hidden-Markov-Model- (HMM-) based search algorithm, we identified several PETase candidates from Flavobacteriaceae and Porphyromonadaceae. Among them, two promiscuous and cold-active esterases derived from Aequorivita sp. (PET27) and Kaistella jeonii (PET30) showed depolymerizing activity on polycaprolactone (PCL), amorphous PET foil and on the polyester polyurethane Impranil((a)) DLN. PET27 is a 37.8 kDa enzyme that released an average of 174.4 nmol terephthalic acid (TPA) after 120 h at 30 degreesC from a 7 mg PET foil platelet in a 200 microl reaction volume, 38-times more than PET30 (37.4 kDa) released under the same conditions. The crystal structure of PET30 without its C-terminal Por-domain (PET30deltaPorC) was solved at 2.1 A and displays high structural similarity to the IsPETase. PET30 shows a Phe-Met-Tyr substrate binding motif, which seems to be a unique feature, as IsPETase, LCC and PET2 all contain Tyr-Met-Trp binding residues, while PET27 possesses a Phe-Met-Trp motif that is identical to Cut190. Microscopic analyses showed that K. jeonii cells are indeed able to bind on and colonize PET surfaces after a few days of incubation. Homologs of PET27 and PET30 were detected in metagenomes, predominantly aquatic habitats, encompassing a wide range of different global climate zones and suggesting a hitherto unknown influence of this bacterial phylum on man-made polymer degradation.
https://www.researchsquare.com/article/rs-567691/v2
Polyethylene terephthalate (PET) is an important synthetic polymer accumulating in nature 2 and recent studies have identified microorganisms capable of degrading PET. While the majority of 3 known PET hydrolases originate from the Actinobacteria and Proteobacteria, here we describe the 4 first functional PET-active enzymes from the Bacteroidetes phylum. Using a PETase-specific 5 Hidden-Markov-Model (HMM)-based search algorithm we identified two promiscuous and cold6 active esterases derived from Aequorivita sp. (PET27) and Chryseobacterium jeonii (PET30) acting 7 on PET foil and powder. Notably, one of the enzymes (PET30) was able to hydrolyze PET at 8 temperatures between 4 - 30 C with a similar turnover rate compared to the well-known Ideonella 9 sakaiensis enzyme (IsPETase). 10 PET27 and PET30 homologues were detected in metagenomes encompassing a wide range 11 of different global climate zones. Additional transcript abundance mapping of marine samples imply 12 that these promiscuous enzymes and source organisms may play a role in the long-term 13 degradation of microplastic particles and fibers.
