Muñoz Javier, Fernández-Irigoyen Joaquín, Santamaría Enrique, Parbel Axel, Obeso José, Corrales Fernando J
Division of Hepatology and Gene Therapy, Proteomics Unit and Division of Neurosciences, Center for Applied Medical Research (CIMA), University Hospital of Navarra (CUN), University of Navarra, Pamplona, Spain.
Proteomics. 2008 May;8(9):1898-908. doi: 10.1002/pmic.200701085.
In the present study, we have used a combination of 2-DE and MS to isolate and characterize two variants of the mitochondrial complex I subunit NDUFA10 from Wistar rat brain. Extensive MS/MS analysis revealed that a D/N substitution at position 120 resulting from a 353A/G transition in the coding gene is the biochemical difference between the two most abundant NDUFA10 isoforms. Moreover, 33 modifications of distinct chemical nature targeting 59 specific residues were found to be common to the acidic and basic forms. Positions C67, H149 and H322 of NDUFA10 were specially targeted by different modifications suggesting the high reactivity of these residues and their potential implication in the regulation of the protein function. Together with nonenzymatic modifications that can form in the sample isolation and workup steps, such as oxidation of methionine, tryptophan, cysteine and histidine, we describe amino acid variants of unknown chemical structure that must be further characterized, as well as accumulation of R, K and H methylations and probably K acetylations at the C-terminal region that might play a role in the control of NDUFA10 activity according to similar mechanisms to those described for histones.
在本研究中，我们使用二维电泳（2-DE）和质谱（MS）相结合的方法，从Wistar大鼠脑部分离并鉴定了线粒体复合物I亚基NDUFA10的两种变体。广泛的串联质谱（MS/MS）分析表明，编码基因中353A/G转换导致第120位发生D/N替换，这是两种最丰富的NDUFA10同工型之间的生化差异。此外，发现针对59个特定残基的33种不同化学性质的修饰在酸性和碱性形式中是常见的。NDUFA10的C67、H149和H322位点被不同修饰特别靶向，表明这些残基具有高反应性及其在蛋白质功能调节中的潜在作用。连同在样品分离和处理步骤中可能形成的非酶修饰，如甲硫氨酸、色氨酸、半胱氨酸和组氨酸的氧化，我们描述了化学结构未知的氨基酸变体，这些变体必须进一步表征，以及在C末端区域R、K和H甲基化的积累以及可能的K乙酰化，根据与组蛋白所描述的类似机制，这些可能在NDUFA10活性的控制中发挥作用。
