Zhang, HongliPerez-Garcia, PabloDierkes, Robert F.Applegate, ViolettaSchumacher, JuliaChibani, Cynthia MariaSternagel, StefaniePreuss, LenaWeigert, SebastianSchmeisser, ChristelDanso, DominikPleiss, JuergenAlmeida, AlexandreHöcker, BirteHallam, Steven J.Schmitz, Ruth A.Smits, Sander H. J.Chow, JenniferStreit, Wolfgang R.2024-03-152024-03-1520221664-302X188377909Xhttp://nbn-resolving.de/urn:nbn:de:bsz:93-opus-ds-140935http://elib.uni-stuttgart.de/handle/11682/14093http://dx.doi.org/10.18419/opus-14074Certain 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® DLN. PET27 is a 37.8 kDa enzyme that released an average of 174.4 nmol terephthalic acid (TPA) after 120 h at 30°C from a 7 mg PET foil platelet in a 200 μl 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 (PET30ΔPorC) was solved at 2.1 Å 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.eninfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by/4.0/540570article2023-11-14