Ficko-Blean Elizabeth, Duffieux Delphine, Rebuffet Étienne, Larocque Robert, Groisillier Agnes, Michel Gurvan, Czjzek Mirjam
Sorbonne Universités, UPMC Université Paris 06, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, 29688 Roscoff CEDEX, France.
Acta Crystallogr D Biol Crystallogr. 2015 Feb;71(Pt 2):209-23. doi: 10.1107/S1399004714025024. Epub 2015 Jan 23.
The family 117 glycoside hydrolase (GH117) enzymes have exo-α-1,3-(3,6-anhydro)-L-galactosidase activity, removing terminal nonreducing α-1,3-linked 3,6-anhydro-L-galactose residues from their red algal neoagarose substrate. These enzymes have previously been phylogenetically divided into clades, and only the clade A enzymes have been experimentally studied to date. The investigation of two GH117 enzymes, Zg3615 and Zg3597, produced by the marine bacterium Zobellia galactanivorans reveals structural, biochemical and further phylogenetic diversity between clades. A product complex with the unusual β-3,6-anhydro-L-galactose residue sheds light on the inverting catalytic mechanism of the GH117 enzymes as well as the structure of this unique sugar produced by hydrolysis of the agarophyte red algal cell wall.
家族117糖苷水解酶（GH117）具有外切α-1,3-（3,6-脱水）-L-半乳糖苷酶活性，可从其红藻新琼脂糖底物上除去末端非还原性α-1,3-连接的3,6-脱水-L-半乳糖残基。这些酶先前已在系统发育上分为不同的进化枝，迄今为止，只有进化枝A中的酶经过了实验研究。对海洋细菌食半乳糖琼氏杆菌产生的两种GH117酶Zg3615和Zg3597的研究揭示了不同进化枝之间在结构、生化以及系统发育方面的多样性。一种与不寻常的β-3,6-脱水-L-半乳糖残基形成的产物复合物，揭示了GH117酶的转化催化机制以及由琼脂藻类红藻细胞壁水解产生的这种独特糖类的结构。
