Department of Chemistry & Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, SC 29208, United States.
Bioorg Chem. 2010 Apr;38(2):62-73. doi: 10.1016/j.bioorg.2009.11.004. Epub 2009 Nov 29.
Helicobacter pylori encodes a potential virulence factor, agmatine deiminase (HpAgD), which catalyzes the conversion of agmatine to N-carbamoyl putrescine (NCP) and ammonia - agmatine is decarboxylated arginine. Agmatine is an endogenous human cell signaling molecule that triggers the innate immune response in humans. Unlike H. pylori, humans do not encode an AgD; it is hypothesized that inhibition of this enzyme would increase the levels of agmatine, and thereby enhance the innate immune response. Taken together, these facts suggest that HpAgD is a potential drug target. Herein we describe the optimized expression, isolation, and purification of HpAgD (10-30 mg/L media). The initial kinetic characterization of this enzyme has also been performed. Additionally, the crystal structure of wild-type HpAgD has been determined at 2.1A resolution. This structure provides a molecular basis for the preferential deimination of agmatine, and identifies Asp198 as a key residue responsible for agmatine recognition, which has been confirmed experimentally. Information gathered from these studies led to the development and characterization of a novel class of haloacetamidine-based HpAgD inactivators. These compounds are the most potent AgD inhibitors ever described.
幽门螺杆菌编码一种潜在的毒力因子，胍氨酸脱亚氨酶（HpAgD），它催化胍氨酸转化为 N-碳酰胺腐胺（NCP）和氨 - 胍氨酸脱羧精氨酸。胍氨酸是一种内源性的人类细胞信号分子，在人类中引发先天免疫反应。与幽门螺杆菌不同，人类不编码 AgD；据推测，抑制这种酶会增加胍氨酸的水平，从而增强先天免疫反应。综上所述，这些事实表明 HpAgD 是一个潜在的药物靶点。本文描述了 HpAgD（10-30mg/L 培养基）的优化表达、分离和纯化。还对该酶的初始动力学特性进行了描述。此外，还确定了野生型 HpAgD 的晶体结构，分辨率为 2.1A。该结构为胍氨酸的优先脱亚氨基提供了分子基础，并确定了 Asp198 是负责胍氨酸识别的关键残基，这已通过实验得到证实。这些研究收集的信息导致了一类新型卤代乙酰胺基 HpAgD 失活剂的开发和表征。这些化合物是迄今为止描述的最有效的 AgD 抑制剂。
