Fig. 1: Subsites I and II of polyester hydrolases. | Nature Communications

Fig. 1: Subsites I and II of polyester hydrolases.

From: Structure and function of the metagenomic plastic-degrading polyester hydrolase PHL7 bound to its product

Fig. 1: Subsites I and II of polyester hydrolases.The alternative text for this image may have been generated using AI.

a Surface representation of PHL7×TPA. TPA (gray) binds to subsite I (blue). Residues comprising the putative subsite II are conserved or semi-conserved (light green), cover a loop that is elongated in mesophilic homologs (dark green) or differ significantly between polyester hydrolases (red). b Superimposition of PHL7×TPA (light blue) with IsPETase (salmon, PDB ID: 5XJH). An extended loop covering residues C239-Q247 of IsPETase deviates from its equivalent region (V211-D216) of PHL7 and is stabilized by a non-conserved disulfide bridge (C203-C239). Activity-regulating L210 lies upstream of that loop and spatially close to H130. c Comparison of structurally equivalent active site residues of PHL7 and its homologs LCC, TfCut2 and IsPETase. The catalytic triad and subsite I residues are conserved or conservatively substituted. Residues equivalent to L93, Q95, H185 and F189 in PHL7 can be considered as a part of subsite I although they do not directly interact with TPA in the cocrystal structure. Subsite II residues and the adjacent loop deviate more significantly, especially among thermophilic (type I) and mesophilic (type IIb) homologs. The loop-stabilizing disulfide bridge of IsPETase is not conserved in type I polyester hydrolases.

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