| 纯度 | >90%SDS-PAGE. |
| 种属 | E.coli |
| 靶点 | speB |
| Uniprot No | B7LFJ6 |
| 内毒素 | < 0.01EU/μg |
| 表达宿主 | E.coli |
| 表达区间 | 1-306aa |
| 氨基酸序列 | MSTLGHQYDNSLVSNAFGFLRLPMNFQPYDSDADWVITGVPFDMATSGRAGGRHGPAAIRQVSTNLAWEHNRFPWNFDMRERLNVVDCGDLVYAFGDAREMSEKLQAHAEKLLAAGKRMLSFGGDHFVTLPLLRAHAKHFGKMALVHFDAHTDTYANGCEFDHGTMFYTAPKEGLIDPNHSVQIGIRTEFDIDNGFTVLDACQVNDRSVDDVIAQVKQIVGDMPVYLTFDIDCLDPAFAPGTGTPVIGGLTSDRAIKLVRGLKDLNIVGMDVVEVAPAYDQSEITALAAATLALEMLYIQAAKKGE |
| 预测分子量 | 49.5 kDa |
| 蛋白标签 | His tag N-Terminus |
| 缓冲液 | PBS, pH7.4, containing 0.01% SKL, 1mM DTT, 5% Trehalose and Proclin300. |
| 稳定性 & 储存条件 | Lyophilized protein should be stored at ≤ -20°C, stable for one year after receipt. Reconstituted protein solution can be stored at 2-8°C for 2-7 days. Aliquots of reconstituted samples are stable at ≤ -20°C for 3 months. |
| 复溶 | Always centrifuge tubes before opening.Do not mix by vortex or pipetting. It is not recommended to reconstitute to a concentration less than 100μg/ml. Dissolve the lyophilized protein in distilled water. Please aliquot the reconstituted solution to minimize freeze-thaw cycles. |
以下是关于SpeB重组蛋白的3篇代表性文献的简要信息整理(示例内容，非真实文献)：
1. **《Crystal structure of Streptococcus pyogenes SpeB reveals a catalytic mechanism unique to cysteine proteases》**
- 作者：Smith J, et al.
- 摘要：通过X射线晶体学解析SpeB蛋白酶的三维结构，揭示了其底物结合位点的独特构象，并阐明了其催化机制与其他半胱氨酸蛋白酶的区别，为设计特异性抑制剂奠定基础。
2. **《Role of SpeB in Group A Streptococcus pathogenesis: Insights from a murine infection model》**
- 作者：Li Y, et al.
- 摘要：利用基因敲除菌株和重组SpeB蛋白，证明SpeB通过降解宿主补体蛋白C3b和免疫球蛋白G，抑制中性粒细胞趋化作用，从而增强GAS在感染早期的免疫逃逸能力。
3. **《Recombinant SpeB as a potential vaccine candidate against Streptococcus pyogenes》**
- 作者：Wang H, et al.
- 摘要：实验表明，纯化的重组SpeB蛋白在小鼠模型中可诱导中和抗体，显著降低致死性GAS感染后的死亡率，提示其作为亚单位疫苗组分的开发潜力。
4. **《Proteolytic activity of SpeB modulates biofilm formation in Streptococcus pyogenes》**
- 作者：Garcia R, et al.
- 摘要：通过体外实验发现，重组SpeB通过切割菌毛相关蛋白破坏细菌生物膜形成，表明SpeB在GAS从定植向侵袭性感染转变中起动态调控作用。
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**注**：以上为基于领域知识的模拟文献，实际引用时请以真实数据库(如PubMed、Web of Science)检索结果为准，并核对作者、标题及摘要准确性。
Streptococcal pyrogenic exotoxin B (SpeB) is a key virulence factor produced by *Streptococcus pyogenes* (Group A Streptococcus, GAS), a bacterial pathogen responsible for infections ranging from pharyngitis to life-threatening invasive diseases. As a cysteine protease, SpeB plays multifaceted roles in GAS pathogenesis, including degrading host extracellular matrix proteins (e.g., fibronectin), cleaving immunoglobulins and complement components to evade immune responses, and processing bacterial surface proteins to promote colonization. Its activity is tightly regulated; SpeB is initially secreted as an inactive zymogen (pro-SpeB) that undergoes autocatalytic maturation under specific pH conditions.
The recombinant SpeB protein, generated via molecular cloning and expression in heterologous systems (e.g., *E. coli* or yeast), has become a critical tool for studying its structure-function relationships and pathogenic mechanisms. Recombinant technology allows large-scale production of high-purity SpeB, enabling detailed biochemical analyses, such as substrate specificity and inhibition assays. Structural studies using recombinant SpeB have revealed its unique papain-like fold and catalytic triad, providing insights into its activation mechanism and substrate-binding sites.
Research on recombinant SpeB also explores its therapeutic potential. Inhibitors targeting SpeB’s protease activity are investigated as novel anti-virulence agents to mitigate GAS infections. Conversely, SpeB’s immunomodulatory properties have prompted studies on its utility in vaccine development or as a diagnostic marker for severe infections. However, challenges remain, including understanding its context-dependent roles (e.g., pro-inflammatory vs. immunosuppressive effects) and balancing its enzymatic stability for clinical applications. Ongoing work aims to harness recombinant SpeB’s dual nature—both as a pathogenic effector and a tool for combating streptococcal diseases.
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