Elucidation of the Role of the Heme Regulatory Motif in Heme Oxygenase-2

阐明血红素调节基序在 Heme Oxygenase-2 中的作用

• 批准号: 7471874
• 负责人: Stephen Wiley Ragsdale
• 金额: $ 22.04万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7471874
• 关键词: Affect; Affinity; Biliverdine; Binding; Biochemical; Blood; C-terminal; Carotid Body; Condition; Disulfides; Electrophysiology (science); Environmental air flow; Exhibits; Gap Junctions; Heme; Hypoxia; In Vitro; Iron; Kinetics; Ligands; Location; Measurement; Measures; Metals; Methods; Molecular Genetics; Nexus (resin cement); Organ; Oxidation-Reduction; Oxygen; Oxygenases; Physiological; Potassium Channel; Property; Proteins; Public Health; Research; Role; Series; Structure; Sulfhydryl Compounds; System; base; design; disulfide bond; genetic regulatory protein; heme d; heme oxygenase-1; heme oxygenase-2; in vivo; large-conductance calcium-activated potassium channels; research study; response

DESCRIPTION (provided by applicant): Heme oxygenase catalyzes the conversion of heme to biliverdin, CO, and iron. The two forms of heme oxygenase (heme oxygenase-1 and heme oxygenase-2) share similar physical and kinetic properties but exhibit different physiological roles and organ locations. The linkage between heme oxygenase-2 and a Caactivated high conductance potassium channel (the BK or Slopoke channel) has been strongly implicated in the control of ventilation by the carotid body in response to changes in the blood oxygen concentration. The major apparent distinction between the sequences of heme oxygenase-1 and heme oxygenase-2 is the occurrence of heme responsive (or regulatory) motifs (HRMs) in heme oxygenase-2. The interaction of heme with HRMs has been proposed to control the activity or stability of several regulatory proteins. Based on recent results, HRM does not bind heme per se or affect HO-2 stability, but appears to act as a redox switch involved in regulating the affinity of heme oxygenase-2 for heme and the spin state of the ferric heme. We plan to use spectroscopic, kinetic, molecular genetic, and electrophysiology studies to determine the role of the HRM in controlling heme oxygenase-2 structure and function. We will characterize the heme and HRM thiol/disulfide redox centers in heme oxygenase-2 by spectroscopic and kinetic methods and determine the redox state of the HRM in vitro and in vivo under various physiological conditions. We also will perform spectroscopic and electrophysiology measurements to determine the mechanism by which heme oxygenase-2 influences BK channel function. PUBLIC HEALTH RELEVANCE Heme oxygenase is the only mammalian protein known to degrade heme and sits at the nexus of several major redox and metal regulatory systems. Two Heme Regulatory Motifs at the C- terminal end of heme oxygenase-2 (HO-2) differentiate it from heme oxygenase-1. This proposal is aimed at determining how(s) these Heme Regulatory Motifs regulate the enzymatic and regulatory properties of HO-2.

描述（由申请人提供）：血红素加氧酶催化血红素转化为胆绿素、CO 和铁。两种形式的血红素加氧酶（血红素加氧酶-1 和血红素加氧酶-2）具有相似的物理和动力学特性，但表现出不同的生理作用和器官位置。血红素加氧酶-2 和 Ca 激活的高电导钾通道（BK 或 Slopoke 通道）之间的联系与颈动脉体响应血氧浓度变化的通气控制密切相关。血红素加氧酶 1 和血红素加氧酶 2 序列之间的主要明显区别是血红素加氧酶 2 中血红素响应（或调节）基序 (HRM) 的出现。血红素与 HRM 的相互作用已被提议用于控制多种调节蛋白的活性或稳定性。根据最近的结果，HRM 本身不结合血红素或影响 HO-2 稳定性，但似乎充当氧化还原开关，参与调节血红素加氧酶-2 对血红素的亲和力以及铁血红素的自旋状态。我们计划利用光谱、动力学、分子遗传学和电生理学研究来确定 HRM 在控制血红素加氧酶 2 结构和功能中的作用。我们将通过光谱和动力学方法表征血红素加氧酶-2中的血红素和HRM硫醇/二硫化物氧化还原中心，并确定HRM在体外和体内在各种生理条件下的氧化还原状态。我们还将进行光谱和电生理学测量，以确定血红素加氧酶 2 影响 BK 通道功能的机制。公共卫生相关性 血红素加氧酶是唯一已知能降解血红素的哺乳动物蛋白质，位于几个主要氧化还原和金属调节系统的联系处。血红素加氧酶 2 (HO-2) C 末端的两个血红素调节基序将其与血红素加氧酶 1 区分开来。该提案旨在确定这些血红素调节基序如何调节 HO-2 的酶促和调节特性。