8GUL

Chitin-active AA10 LPMO (GbpA) complexed with Cu(II) from Vibrio campbellii

8GUL の概要

• エントリーDOI: 10.2210/pdb8gul/pdb
• 分子名称: GlcNAc-binding protein A, COPPER (II) ION, SULFATE ION, ... (4 entities in total)
• 機能のキーワード: lpmo, chitin degradation, cu(ii)-dependent enzyme., metal binding protein
• 由来する生物種: Vibrio campbellii ATCC BAA-1116
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 102588.84

構造登録者

Zhou, Y.,Robinson, R.C.,Suginta, W. (登録日: 2022-09-12, 公開日: 2023-06-21, 最終更新日: 2024-10-16)

主引用文献

Zhou, Y.,Wannapaiboon, S.,Prongjit, M.,Pornsuwan, S.,Sucharitakul, J.,Kamonsutthipaijit, N.,Robinson, R.C.,Suginta, W.
Structural and binding studies of a new chitin-active AA10 lytic polysaccharide monooxygenase from the marine bacterium Vibrio campbellii.
Acta Crystallogr D Struct Biol, 79:479-497, 2023

PubMed Abstract: Vibrio spp. play a crucial role in the global recycling of the highly abundant recalcitrant biopolymer chitin in marine ecosystems through their ability to secrete chitin-degrading enzymes to efficiently hydrolyse chitinous materials and use them as their major carbon source. In this study, the first crystal structures of a complete four-domain chitin-active AA10 lytic polysaccharide monooxygenase from the chitinolytic bacterium Vibrio campbellii type strain ATCC BAA-1116 are reported. The crystal structures of apo and copper-bound VhLPMO10A were resolved as homodimers with four distinct domains: an N-terminal AA10 catalytic (CatD) domain connected to a GlcNAc-binding (GbpA_2) domain, followed by a module X domain and a C-terminal carbohydrate-binding module (CBM73). Size-exclusion chromatography and small-angle X-ray scattering analysis confirmed that VhLPMO10A exists as a monomer in solution. The active site of VhLPMO10A is located on the surface of the CatD domain, with three conserved residues (His1, His98 and Phe170) forming the copper(II)-binding site. Metal-binding studies using synchrotron X-ray absorption spectroscopy and X-ray fluorescence, together with electron paramagnetic resonance spectroscopy, gave consistently strong copper(II) signals in the protein samples, confirming that VhLPMO10A is a copper-dependent enzyme. ITC binding data showed that VhLPMO10A could bind various divalent cations but bound most strongly to copper(II) ions, with a K of 0.1 ± 0.01 µM. In contrast, a K of 1.9 nM was estimated for copper(I) ions from redox-potential measurements. The presence of ascorbic acid is essential for HO production in the reaction catalysed by VhLPMO10A. MALDI-TOF MS identified VhLPMO10A as a C1-specific LPMO, generating oxidized chitooligosaccharide products with different degrees of polymerization (DP2-DP8). This new member of the chitin-active AA10 LPMOs could serve as a powerful biocatalyst in biofuel production from chitin biomass.

PubMed: 37259836
DOI: 10.1107/S2059798323003261

実験手法

X-RAY DIFFRACTION (2.44 Å)