Glutathionylation Induced Structural Changes in Oxy Human Hemoglobin Analyzed by Backbone Amide Hydrogen/Deuterium Exchange and MALDI-Mass Spectrometry

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• 作者：Gopa Mitra ; Monita Muralidharan ; Sreekala Narayanan ; Jennifer Pinto ; Krishnamachari Srinivasan ; Amit Kumar Mandal
• 刊名：Bioconjugate Chemistry
• 出版年：2012
• 出版时间：December 19, 2012
• 年：2012
• 卷：23
• 期：12
• 页码：2344-2353
• 全文大小：392K
• 年卷期：v.23,no.12(December 19, 2012)
• ISSN：1520-4812

文摘

Glutathionyl hemoglobin, a post-translationally modified form of hemoglobin, has been reported to serve as a marker of oxidative stress in several clinical conditions. This modification causes perturbations in the hemoglobin functionality by increasing oxygen affinity and reducing cooperativity. Moreover, glutathionylation of sickle hemoglobin was reported to lead to a significant reduction in the propensity of sickling of erythrocytes. The root cause of the above functional abnormality is not known in detail, as the crystal structure of the molecule is yet to be discovered. In this study, we investigated the effects of glutathionylation on quaternary structure of hemoglobin using hydrogen/deuterium exchange (H/DX) based mass spectrometry. H/DX kinetics of nine peptides from 伪 and 尾 globin chains of hemoglobin were analyzed to understand the conformational change in deoxy to oxy transition of normal hemoglobin and structural perturbations associated with glutathionylation of oxy hemoglobin. Significant structural changes brought about by the glutathionylation of oxy hemoglobin were observed in the following regions of globin chains: 尾86鈥?02, 尾1鈥?4, 伪34鈥?6, 尾32鈥?1, 尾130鈥?46, 尾115鈥?29, 尾73鈥?1. Isotope exchange kinetics monitored through mass spectrometry is a useful technique to understand structural perturbation on post-translational modification of proteins in solution phase.