Regulation of nitrite reductase and lipid binding properties of cytoglobin by surface and distal histidine mutations.
Regulation of nitrite reductase and lipid binding properties of cytoglobin by surface and distal histidine mutations.
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DOI：
10.1016/j.niox.2022.06.001
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发表时间：
2022-08-01
影响因子：
3.9
通讯作者：
Tejero, Jests
中科院分区：
文献类型：
--
作者：
Kaliszuk, Stefan J.;Morgan, Natasha I.;Ayers, Taylor N.;Sparacino-Watkins, Courtney E.;DeMartino, Anthony W.;Bocian, Kaitlin;Ragireddy, Venkata;Tong, Qin;Tejero, Jests
细胞红蛋白是一种广泛表达于成纤维细胞及相关细胞系的血红蛋白，其生理功能尚未明确。与其他血红素蛋白一样，细胞红蛋白可以将亚硝酸盐还原为一氧化氮（NO），为体内低氧条件下生成NO提供了一条途径。此外，细胞红蛋白还能以高亲和力结合油酸、心磷脂等脂质。这两个过程可能与细胞红蛋白的功能有关。关于特定氨基酸如何促进亚硝酸盐还原和脂质结合，我们知之甚少。在这里，我们研究了远端组氨酸His81（E7）和几个表面残基在调控亚硝酸盐还原和脂质结合中的作用。我们观察到His81（E7）的替换极大地提高了血红素对亚硝酸盐的反应性，His81Ala突变体的亚硝酸盐还原速率常数高达1100 M−1s−1。His81（E7）突变导致脂质结合亲和力小幅下降，但咪唑存在的实验表明，His81（E7）不与脂质竞争结合位点。表面残基Arg84和Lys116的突变在很大程度上损害了脂质结合。我们的研究结果表明，His81（E7）与血红素的解离介导了血红素近端疏水腔的形成，可以容纳脂质，其中Thr91， Val105和Leu108残基周围的疏水斑块是重要的贡献，而Arg84和Lys116的正电荷则稳定了脂肪酸的羧基。这里描述的功能获得和功能丧失突变可以作为研究这些假定的细胞红蛋白功能在体内生理作用的工具。
Cytoglobin is a hemoprotein widely expressed in fibroblasts and related cell lineages with yet undefined physiological function. Cytoglobin, as other heme proteins, can reduce nitrite to nitric oxide (NO) providing a route to generate NO in vivo in low oxygen conditions. In addition, cytoglobin can also bind lipids such as oleic acid and cardiolipin with high affinity. These two processes are potentially relevant to cytoglobin function. Little is known about how specific amino acids contribute to nitrite reduction and lipid binding. Here we investigate the role of the distal histidine His81(E7) and several surface residues on the regulation of nitrite reduction and lipid binding. We observe that the replacement of His81(E7) greatly increases heme reactivity towards nitrite, with nitrite reduction rate constants of up to 1100 M−1s−1 for the His81Ala mutant. His81(E7) mutation causes a small decrease in lipid binding affinity, however experiments on the presence of imidazole indicate that His81(E7) does not compete with the lipid for the binding site. Mutations of the surface residues Arg84 and Lys116 largely impair lipid binding. Our results suggest that dissociation of His81(E7) from the heme mediates the formation of a hydrophobic cavity in the proximal heme side that can accommodate the lipid, with important contributions of the hydrophobic patch around residues Thr91, Val105, and Leu108, whereas the positive charges from Arg84 and Lys116 stabilize the carboxyl group of the fatty acid. Gain and loss-of-function mutations described here can serve as tools to study in vivo the physiological role of these putative cytoglobin functions.
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影响因子：
3.9
作者：
Corti, Paola;Ieraci, Matthew;Tejero, Jesus
通讯作者：
Tejero, Jesus
影响因子：
3.7
作者：
Gabba, Matteo;Abbruzzetti, Stefania;Dewilde, Sylvia
通讯作者：
Dewilde, Sylvia
影响因子：
82.9
作者：
Cosby, K;Partovi, KS;Gladwin, MT
通讯作者：
Gladwin, MT
影响因子：
7.4
作者：
Kagan, Valerian E.;Bayir, Huelya A.;Belikova, Natalia A.;Kapralov, Olexandr;Tyurina, Yulia Y.;Tyurin, Vladimir A.;Jiang, Jianfei;Stoyanovsky, Detcho A.;Wipf, Peter;Kochanek, Patrick M.;Greenberger, Joel S.;Pitt, Bruce;Shvedova, Anna A.;Borisenko, Grigory
通讯作者：
Borisenko, Grigory
影响因子：
7.4
作者：
DeMartino AW;Amdahl MB;Bocian K;Rose JJ;Tejero J;Gladwin MT
通讯作者：
Gladwin MT