Structure-informed design of an enzymatically inactive vaccine component for group A Streptococcus.
Structure-informed design of an enzymatically inactive vaccine component for group A Streptococcus.
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DOI：
10.1128/mbio.00509-13
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发表时间：
2013-08-06
期刊：
影响因子：
6.4
通讯作者：
Walker MJ
中科院分区：
文献类型：
--
作者：
Henningham A;Ericsson DJ;Langer K;Casey LW;Jovcevski B;Chhatwal GS;Aquilina JA;Batzloff MR;Kobe B;Walker MJ
化脓性链球菌（A组链球菌[GAS]）每年导致约7亿人感染，导致> 500，000人死亡。目前还没有商业疫苗。GAS表面蛋白精氨酸脱亚胺酶（ADI）保护小鼠免受致死性攻击。ADI是一种将精氨酸转化为瓜氨酸和氨的酶。给予含有野生型ADI（一种具有固有酶活性的蛋白质）的GAS疫苗制剂可能存在安全性风险。在一种旨在最大限度地提高GAS ADI疫苗安全性的方法中，使用X射线晶体学和结构免疫原性表位作图来为疫苗设计提供信息。本研究旨在敲除ADI酶活性而不破坏三维结构或免疫原性表位的识别。我们在2.5 nm分辨率下测定了ADI的晶体结构，并使用它选择了许多氨基酸残基用于突变为丙氨酸（D166、E220、H275、D277和C401）。每个突变蛋白显示废除的活动，和三个突变蛋白（D166A，H275A，和D277A突变）具有二级结构和寡聚化状态等同于野生型，产生高滴度抗血清，并避免破坏ADI的B细胞表位。此外，针对D166A和D277A突变蛋白产生的抗血清结合到GAS细胞表面。灭活的D166A和D277A突变ADI是包含在GAS疫苗制剂中的理想选择。没有ADI的人类直系同源物，我们证实，尽管在活性位点区域与人肽基ADI 4（PAD4）的结构相似性有限，但ADI在功能上不模拟PAD4，并且针对GAS ADI产生的抗血清不识别人PAD4。我们提出了一个为人类疫苗设计提供信息的结构生物学例子。我们以前表明，精氨酸脱亚胺酶（ADI）的管理，以保护小鼠免受感染多种GAS血清型。在这项研究中，我们确定了GAS ADI的结构，并利用这些信息来提高GAS ADI的疫苗安全性。ADI的催化失活突变形式保留了结构、抗血清识别和免疫原性表位，使其成为GAS疫苗制剂的理想选择。这个结构生物学告知疫苗设计的例子可能支持安全有效的GAS疫苗的配制。
Streptococcus pyogenes (group A Streptococcus [GAS]) causes ~700 million human infections/year, resulting in >500,000 deaths. There is no commercial GAS vaccine available. The GAS surface protein arginine deiminase (ADI) protects mice against a lethal challenge. ADI is an enzyme that converts arginine to citrulline and ammonia. Administration of a GAS vaccine preparation containing wild-type ADI, a protein with inherent enzymatic activity, may present a safety risk. In an approach intended to maximize the vaccine safety of GAS ADI, X-ray crystallography and structural immunogenic epitope mapping were used to inform vaccine design. This study aimed to knock out ADI enzyme activity without disrupting the three-dimensional structure or the recognition of immunogenic epitopes. We determined the crystal structure of ADI at 2.5 Å resolution and used it to select a number of amino acid residues for mutagenesis to alanine (D166, E220, H275, D277, and C401). Each mutant protein displayed abrogated activity, and three of the mutant proteins (those with the D166A, H275A, and D277A mutations) possessed a secondary structure and oligomerization state equivalent to those of the wild type, produced high-titer antisera, and avoided disruption of B-cell epitopes of ADI. In addition, antisera raised against the D166A and D277A mutant proteins bound to the GAS cell surface. The inactivated D166A and D277A mutant ADIs are ideal for inclusion in a GAS vaccine preparation. There is no human ortholog of ADI, and we confirm that despite limited structural similarity in the active-site region to human peptidyl ADI 4 (PAD4), ADI does not functionally mimic PAD4 and antiserum raised against GAS ADI does not recognize human PAD4. We present an example of structural biology informing human vaccine design. We previously showed that the administration of the enzyme arginine deiminase (ADI) to mice protected the mice against infection with multiple GAS serotypes. In this study, we determined the structure of GAS ADI and used this information to improve the vaccine safety of GAS ADI. Catalytically inactive mutant forms of ADI retained structure, recognition by antisera, and immunogenic epitopes, rendering them ideal for inclusion in GAS vaccine preparations. This example of structural biology informing vaccine design may underpin the formulation of a safe and efficacious GAS vaccine.