Structural mechanisms for the S-nitrosylation-derived protection of mouse galectin-2 from oxidation-induced inactivation revealed by NMR
Structural mechanisms for the S-nitrosylation-derived protection of mouse galectin-2 from oxidation-induced inactivation revealed by NMR
复制标题
NMR揭示了S-亚硝基化衍生的小鼠半乳糖凝集素2免受氧化诱导失活的保护结构机制
DOI：
10.1111/febs.14397
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
and Takahashi H.
中科院分区：
文献类型：
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作者：
Sakakura M;Tamura M;Fujii N;Takeuchi T;Hatanaka T;Kishimoto S;Arata Y;and Takahashi H.
Galectin-2（Gal-2）是一种被认为在胃肠道中发挥保护作用的凝集素。小鼠Gal-2（mGal-2）被过氧化氢（H2 O2）氧化会导致糖结合活性丧失，而mGal-2的S-亚硝基化不会改变其糖结合特征，已被证明可以保护蛋白质免受H2 O2诱导的失活。两个半胱氨酸残基之一，C57，已被确定为负责控制H2 O2诱导的失活;然而，潜在的分子机制尚未阐明。我们使用核磁共振（NMR）对mGal-2进行了结构分析，发现C57附近的残基在S-亚硝基化后发生了显著的化学位移变化，并且S-亚硝基化减缓了H2 O2诱导的mGal-2聚集。我们还发现，S-亚硝基化提高了mGal-2的热稳定性，并且通过S-亚硝基化降低了mGal-2中C57附近残基的溶剂可及性和/或局部动力学以及核心形成残基的局部动力学。Gal-2的结构模型表明，C57位于疏水口袋中，可以通过S-亚硝基化堵塞，这得到了NMR实验的支持。基于这些结果，我们提出了两种结构机制，S-亚硝基化保护mGal-2免受H2 O2诱导的聚集而不改变其糖结合特征：（a）稳定C57周围的疏水口袋，防止口袋的氧化诱导的不稳定化，和（B）在蛋白质的瞬时解折叠状态期间防止C57的氧化，其中残基暴露于H2 O2。数据库非S-亚硝基化mGal-2和S-亚硝基化mGal-2的核磁共振分配已保存在BioMagResBank（http：//www.bmrb.wisc.edu/）中，非S-亚硝基化mGal-2的ID代码为27237，S-亚硝基化mGal-2的ID代码为27238。
Galectin‐2 (Gal‐2) is a lectin thought to play protective roles in the gastrointestinal tract. Oxidation of mouse Gal‐2 (mGal‐2) by hydrogen peroxide (H2O2) results in the loss of sugar‐binding activity, whereas S‐nitrosylation of mGal‐2, which does not change its sugar‐binding profile, has been shown to protect the protein from H2O2‐induced inactivation. One of the two cysteine residues, C57, has been identified as being responsible for controlling H2O2‐induced inactivation; however, the underlying molecular mechanism has not been elucidated. We performed structural analyses of mGal‐2 using nuclear magnetic resonance (NMR) and found that residues near C57 experienced significant chemical shift changes following S‐nitrosylation, and that S‐nitrosylation slowed the H2O2‐induced aggregation of mGal‐2. We also revealed that S‐nitrosylation improves the thermal stability of mGal‐2 and that the solvent accessibility and/or local dynamics of residues near C57 and the local dynamics of the core‐forming residues in mGal‐2 are reduced by S‐nitrosylation. Structural models of Gal‐2 indicated that C57 is located in a hydrophobic pocket that can be plugged by S‐nitrosylation, which was supported by the NMR experiments. Based on these results, we propose two structural mechanisms by which S‐nitrosylation protects mGal‐2 from H2O2‐induced aggregation without changing its sugar‐binding profile: (a) stabilization of the hydrophobic pocket around C57 that prevents oxidation‐induced destabilization of the pocket, and (b) prevention of oxidation of C57 during the transiently unfolded state of the protein, in which the residue is exposed to H2O2.DatabaseNuclear magnetic resonance assignments for non‐S‐nitrosylated mGal‐2 and S‐nitrosylated mGal‐2 have been deposited in the BioMagResBank (http://www.bmrb.wisc.edu/) under ID code 27237 for non‐S‐nitrosylated mGal‐2 and ID code 27238 for S‐nitrosylated mGal‐2.