Structural and functional modifications of corneal crystallin ALDH3A1 by UVB light.
Structural and functional modifications of corneal crystallin ALDH3A1 by UVB light.
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DOI：
10.1371/journal.pone.0015218
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发表时间：
2010-12-21
期刊：
影响因子：
3.7
通讯作者：
Vasiliou V
中科院分区：
文献类型：
--
作者：
Estey T;Chen Y;Carpenter JF;Vasiliou V
乙醛脱氢酶3A1(ALDH3A1)是哺乳动物角膜上皮细胞中表达最丰富的蛋白质之一，在保护角膜免受氧化应激损伤中发挥着重要的、多方面的作用。最近的研究表明，ALDH3A1的保护机制之一是直接吸收紫外线能量，通过竞争机制减少对其他角膜蛋白质的损伤，如葡萄糖-6-磷酸脱氢酶。然而，在这种情况下，紫外线照射会导致ALDH3A1失活。在目前的研究中，我们证明了紫外线通过共价和非共价相互作用引起ALDH3A1的可溶性非天然聚集，聚集体的形成是ALDH3A1酶活性丧失的原因。光谱研究表明，由于聚集，ALDH3A1的二级和三级结构被扰动。用MALDI-TOF质谱仪绘制的LysC肽图表明，紫外线对ALDH3A1的损伤还包括对色氨酸、蛋氨酸和半胱氨酸残基的化学修饰。令人惊讶的是，ALDH3A1的保守活性位点Cys似乎不受紫外线照射的影响；在紫外线照射下，这一残基保持完好，使酶完全失活。综上所述，我们的数据表明，紫外线诱导的ALDH3A1失活是非自然聚集和相关结构变化的结果，而不是对活性位点Cys的特定损伤。
As one of the most abundantly expressed proteins in the mammalian corneal epithelium, aldehyde dehydrogenase 3A1 (ALDH3A1) plays critical and multifaceted roles in protecting the cornea from oxidative stress. Recent studies have demonstrated that one protective mechanism of ALDH3A1 is the direct absorption of UV-energy, which reduces damage to other corneal proteins such as glucose-6-phosphate dehydrogenase through a competition mechanism. UV-exposure, however, leads to the inactivation of ALDH3A1 in such cases. In the current study, we demonstrate that UV-light caused soluble, non-native aggregation of ALDH3A1 due to both covalent and non-covalent interactions, and that the formation of the aggregates was responsible for the loss of ALDH3A1 enzymatic activity. Spectroscopic studies revealed that as a result of aggregation, the secondary and tertiary structure of ALDH3A1 were perturbed. LysC peptide mapping using MALDI-TOF mass spectrometry shows that UV-induced damage to ALDH3A1 also includes chemical modifications to Trp, Met, and Cys residues. Surprisingly, the conserved active site Cys of ALDH3A1 does not appear to be affected by UV-exposure; this residue remained intact after exposure to UV-light that rendered the enzyme completely inactive. Collectively, our data suggest that the UV-induced inactivation of ALDH3A1 is a result of non-native aggregation and associated structural changes rather than specific damage to the active site Cys.
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影响因子：
4.8
作者：
Lassen, Natalie;Bateman, J. Bronwyn;Vasiliou, Vasilis
通讯作者：
Vasiliou, Vasilis
DOI：
10.1038/nsb0497-317
发表时间：
1997-04-01
期刊：
NATURE STRUCTURAL BIOLOGY
影响因子：
--
作者：
Liu, ZJ;Sun, YJ;Wang, BC
通讯作者：
Wang, BC
影响因子：
3.4
作者：
ABEDINIA, M;PAIN, T;HOLMES, RS
通讯作者：
HOLMES, RS
影响因子：
4.8
作者：
Estey, Tia;Cantore, Miriam;Vasiliou, Vasilis
通讯作者：
Vasiliou, Vasilis
影响因子：
3.8
作者：
Estey, Tia;Vessely, Christina;Randolph, Theodore W.;Henderson, Ian;Braun, Latoya Jones;Nayar, Rajiv;Carpenter, John F.
通讯作者：
Carpenter, John F.