Neutron and Atomic Resolution X-ray Structures of a Lytic Polysaccharide Monooxygenase Reveal Copper-Mediated Dioxygen Binding and Evidence for N-Terminal Deprotonation,Biochemistry

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Neutron and Atomic Resolution X-ray Structures of a Lytic Polysaccharide Monooxygenase Reveal Copper-Mediated Dioxygen Binding and Evidence for N-Terminal Deprotonation
Biochemistry ( IF 2.9 ) Pub Date : 2017-05-08 00:00:00 , DOI: 10.1021/acs.biochem.7b00019
John-Paul Bacik ₁ , Sophanit Mekasha ₂ , Zarah Forsberg ₂ , Andrey Y. Kovalevsky ₃ , Gustav Vaaje-Kolstad ₂ , Vincent G. H. Eijsink ₂ , Jay C. Nix ₄ , Leighton Coates ₃ , Matthew J. Cuneo ₃ , Clifford J. Unkefer ₁ , Julian C.-H. Chen ₁

Affiliation

A 1.1 Å resolution, room-temperature X-ray structure and a 2.1 Å resolution neutron structure of a chitin-degrading lytic polysaccharide monooxygenase domain from the bacterium Jonesia denitrificans (JdLPMO10A) show a putative dioxygen species equatorially bound to the active site copper. Both structures show an elongated density for the dioxygen, most consistent with a Cu(II)-bound peroxide. The coordination environment is consistent with Cu(II). In the neutron and X-ray structures, difference maps reveal the N-terminal amino group, involved in copper coordination, is present as a mixed ND₂ and ND^–, suggesting a role for the copper ion in shifting the pK_a of the amino terminus.

中文翻译：

溶解性多糖单加氧酶的中子和原子分辨率X射线结构揭示了铜介导的双氧结合和N端去质子化的证据。

细菌脱氮琼脂菌（Jd LPMO10A）的几丁质降解裂解多糖单加氧酶域的1.1分辨率，室温X射线结构和2.1分辨率中子结构显示了与活性位铜呈赤道键合的推定双氧物种。两种结构均显示出双氧的伸长密度，这与与Cu（II）结合的过氧化物最为一致。配位环境与Cu（II）一致。在中子和X射线结构中，差异图显示参与铜配位的N末端氨基以ND ₂和ND ^–的混合形式存在，表明铜离子在改变P k _a的p K _a中的作用。氨基末端。

更新日期：2017-05-12

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