CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies (IBIOM), via Amendola 122/O, 70126, Bari, Italy.
Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via Bucci 4C, 87036, Arcavacata di Rende, Italy.
Free Radic Biol Med. 2022 Aug 1;188:395-403. doi: 10.1016/j.freeradbiomed.2022.06.244. Epub 2022 Jul 2.
Both toxic and physiological effects of CO are mostly caused by well described interactions with heme-groups of proteins. Interactions of CO with non-heme proteins have also been unveiled. Besides interaction of CO with mitochondrial heme containing respiratory complexes, a BK channel and the phosphate carrier which do not contain metal cofactors, have been identified as CO targets. However, the molecular mechanisms of interaction with non-metal-containing proteins are not understood. We show in this work the effect of CO on the mitochondrial carnitine carrier (SLC25A20) using CORM-3, a widely recognized CO releasing compound. CO exerts an inhibitory effect at the micromolar concentration on the transport function of the transporter extracted from treated mitochondria. The effect is due to a single Cys residue, C136 as revealed by mass spectrometry analysis. A computational approach predicted the need for vicinal Asp and Lys residues for the C136 carbonylation to occur. These data demonstrate a novel mechanism of interaction of CO with a protein not containing metal atoms and will enable the prediction of CO targets.
CO 的毒性和生理作用主要是由其与蛋白质的血红素基团的明确相互作用引起的。CO 与非血红素蛋白的相互作用也已被揭示。除了与含有线粒体血红素的呼吸复合物、BK 通道和不含有金属辅因子的磷酸载体相互作用外，还确定了 CO 作为靶标。然而，与不含金属的蛋白质相互作用的分子机制尚不清楚。我们在这项工作中使用 CORM-3（一种广泛认可的 CO 释放化合物）展示了 CO 对线粒体肉碱载体（SLC25A20）的影响。CO 在从处理的线粒体中提取的转运蛋白的运输功能上以微摩尔浓度发挥抑制作用。该效果归因于单个半胱氨酸残基 C136，如质谱分析所揭示的。计算方法预测需要相邻的 Asp 和 Lys 残基才能发生 C136 的碳化。这些数据证明了 CO 与不含金属原子的蛋白质相互作用的新机制，并将能够预测 CO 的靶标。
