Pectate lyase (PL) holds significant potential for applications in various industries. However, the existing PL was unable to adapt to thermo-alkaline industrial environments. In this work, a PL from Caldicellulosiruptor bescii DSM 6725 (hereafter, CbPelD) was studied to disclose its structural and biochemical properties. CbPelD consisted of a putative signal peptide sequence, a short linker region, and a catalytic domain (PelD-II), along with an exoacting β-fructofuranosidase domain (PelD-I). In molecular dynamics simulation, PelD-II demonstrated significantly higher activity and thermal stability compared to other truncated enzymes of CbPelD. The optimal pH and temperature for PelD-II were 10.0 and 60 °C, respectively, with the specific activity increasing by 164–223% in the presence of Ca2+ or Ni2+. The exotype PelD-II exhibited efficient degradation of polygalacturonic acid (PGA) into unsaturated galacturonic acid (uG1), digalacturonic acid (uG2), and trigalacturonic acid (uG3). In the bioscouring assay, PelD-II exhibited a significant increase in the wetted fabric area to 6.072 ± 0.684 cm2, which was about 7.9 times higher than untreated fabric. Scanning electron microscopy further revealed that treatment with PelD-II resulted in a smoother fiber surface, providing direct visual confirmation of the enzyme’s action. These results highlight the potential of PelD-II for applications in the textile industries.
In this study, a novel pectate lyase ( Ap Pel1) was identified and characterized from Aspergillus parasiticus . The Ap Pel1 hydrolysed oligogalacturonides (OGs) effectively and produced 4,5-unsaturated OGs from low-methoxyl (LM) pectin, with DP 2 to DP 5 as the major products. Furthermore, the multiple sequence alignments , structure model and phylogenetic analyses of the Ap Pel1 indicated that its catalytic active sites were highly conserved with other pectin lyases (PLs) and the Ca 2+ binding amino acid residues are different compared with pectate lyases (Pels). N187D, N191D and N187D/N191D mutants were constructed to test for both Ca 2+ binding properties and the effects on catalytic ability. The three mutations sharply decreased the activity of Ap Pel1 and Ca 2+ tolerance, indicating that the Ca 2+ binding amino acid residues are different from the other Pels. Based on the sequence and structure comparison between PLs and Pels, and mutation analysis, the Ap Pel1 may be direct evolution from PLs. Thus, this enzyme has potential for use in producing unsaturated OGs for biological activity study, and contributes to an improved understanding of the evolutionary relationships between PLs and Pels.
Ling Zheng,Zilong Guo,Yinxiao Xu,Benwei Zhu,Zhong Yao
Pectate lyase (ErPL2) from Echinicola rosea JL3085 showed maximal activity at 45 °C and pH 9.0 with 0.6 mM CaCl 2 . The K m and V max values of ErPL2 for polygalacturonic sodium were 2.098 mmol/L and 0.955 mmol/s, respectively. ErPL2 endolytically degraded pectic substances into oligosaccharides with degree of polymerization (DP) 1–5. To improve the thermostability and pH operation range, recombinant ErPL2 was immobilized onto mesoporous titanium oxide particles (MTOPs). MTOPs have abundant hydroxyl groups on the surface, which is a non-toxicity and good biocompatibility carrier. The residual enzyme activity of immobilized ErPL2 at 40 °C increased remarkably from 11% to 91% compared with free enzyme. The operable pH range was extended from 8–9 to 9–11. Surprisingly, the catalytic efficiency of immobilized ErPL2 was about 19 times higher than free enzyme. To our knowledge this is the first attempt of pectate lyase immobilized on MTOPs and it provides a new option for improving the catalytic performance.
危险品化学品经营许可证（带存储）