Influence of Solvent on the Active Site Environment of Lactoperoxidase

溶剂对乳过氧化物酶活性位点环境的影响

• 批准号: 7539690
• 负责人: Jennifer Lynn Greene
• 金额: $ 4.1万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7539690
• 关键词: Active Sites; Affect; Affinity; Arginine; Bacteria; Binding; Biological Assay; Carbon Monoxide; Cervical; Charge; Child; Circular Dichroism; Classification; Crystallography; Cystic Fibrosis; Disease; Distal; Electron Spin Resonance Spectroscopy; Electrostatics; Environment; Enzymes; Escherichia coli; Family; Frequencies; Functional disorder; Future; Genus staphylococcus; Goals; Heme; Hydrogen Bonding; Hydrogen Peroxide; Infection; Inflammation; Invaded; Iron; Left; Ligand Binding; Ligands; Liquid substance; Lung; Membrane; Methods; Microbe; Mucins; Mucous body substance; Nature; Peroxidase; Peroxidases; Personal Satisfaction; Plants; Play; Population; Process; Prosthesis; Proteins; Role; Saliva; Site; Solvents; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis; Stretching; Structure; System; Temperature; Thiocyanates; Water; Work; absorption; antimicrobial; cryogenics; infrared spectroscopy; lactoperoxidase; member; mutant; pathogen; preference; prevent; protein protein interaction; respiratory; small molecule; thiocyanate; ultraviolet

DESCRIPTION (provided by applicant): A member of the mammalian peroxidase family, lactoperoxidase (LPO) serves as the first line of defense in a variety of secretory fluids including tears, saliva, and cervical fluid. While lactoperoxidase is structurally capable of binding a variety of small molecules to its active site, only thiocyanate (SCN-) interacts with LPO while in the presence of hydrogen peroxide (H2O2) to form a biocidal agent. Recently, LPO was identified as contributing antimicrobial activity against bacteria such as staphylococci and E. coli while present in mammalian respiratory secretions. In cystic fibrosis (CF), a systematic disease characterized by incessant lung infections, inflammation, and increased mucin content, this antimicrobial system has been shown to dysfunction. This work focuses on understanding the structural role that solvent plays in lactoperoxidase's preference for its ligands and ultimately how this preference affects its functionality. The specific aims are as follows: 1) Use various bound ligands to probe the active site heme environment of LPO; 2) Examine the role of distal arginine in ordering water leading to the solvent accessible cavity of LPO; and 3) Characterize the interaction of mucin proteins with lactoperoxidase molecules. Cystic fibrosis (CF) is a particularly menacing disease not only because a large portion of its affected population are children, but also because it is a multi-system disease, making it very difficult to study. Within the airways of those afflicted with CF, lactoperoxidase, an enzyme responsible for attacking invading bacteria, has been shown to be faulty. The goals of this work are to gain a more accurate understanding of how this enzyme works and ultimately provide future directions for more targeted therapies.

描述(申请人提供)：作为哺乳动物过氧化物酶家族的成员，乳过氧化物酶(LPO)在包括泪水、唾液和宫颈分泌液在内的各种分泌液中是第一道防线。虽然乳过氧化物酶在结构上能够将各种小分子结合到其活性部位，但在过氧化氢(H_2O_2)存在下，只有硫氰酸盐(SCN-)与LPO相互作用形成杀菌剂。最近，LPO被证实对哺乳动物呼吸道分泌物中存在的葡萄球菌和大肠杆菌等细菌具有抗菌活性。囊性纤维化是一种全身性疾病，以持续的肺部感染、炎症和粘蛋白含量增加为特征，这种抗菌系统已显示出功能障碍。这项工作的重点是了解溶剂在乳过氧化物酶对其配体的偏好中所起的结构作用，以及这种偏好最终如何影响其功能。其具体目的如下：1)使用不同的结合配体来探测LPO的活性中心血红素环境；2)检测远端精氨酸在有序水中的作用，从而导致LPO的溶剂可达空腔；以及3)表征粘蛋白蛋白与乳过氧化物酶分子的相互作用。囊性纤维化是一种特别危险的疾病，不仅因为它的很大一部分患者是儿童，而且因为它是一种多系统疾病，使得研究非常困难。在患有CF的患者的呼吸道内，负责攻击入侵细菌的乳过氧化物酶已被证明是有缺陷的。这项工作的目标是更准确地了解这种酶是如何工作的，并最终为更有针对性的治疗提供未来的方向。