| 纯度 | >90%SDS-PAGE. |
| 种属 | E.coli |
| 靶点 | lktA |
| Uniprot No | P55118 |
| 内毒素 | < 0.01EU/μg |
| 表达宿主 | E.coli |
| 表达区间 | 1-229aa |
| 氨基酸序列 | MGNKLTNISTNLKSSWLTAKSGLNRTGQSLAKAGQSLKTGAKKIILYIPKDYQYDTEKGNGLQDLVKAAEELGIEVQKEEGNDIAKAQTSLGTIQNVLGLTERGIVLSAPQLDKLLQKTKVGQAIGSAENLTKGFSNAKTVLSGIQSILGSVLAGMDLDEALQKNSNELTLAKAGLELTNSLIENIANSVKTLDAFGDQINQLGSKLQNVKGLSSLGDKLKGLSGFDKT |
| 预测分子量 | 29.2 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3-4条与 **lktA重组蛋白** 相关的参考文献及其简要摘要：
1. **《Cloning and expression of the leukotoxin gene from *Mannheimia haemolytica*》**
- **作者**: Highlander SK, et al.
- **摘要**: 该研究克隆并表达了来自溶血性曼氏杆菌(*Mannheimia haemolytica*)的lktA基因，证实其编码的白细胞毒素(leukotoxin)对牛中性粒细胞具有特异性细胞毒性，为后续疫苗开发奠定基础。
2. **《Recombinant leukotoxin as a vaccine to protect cattle against pneumonic pasteurellosis》**
- **作者**: Tatum FM, et al.
- **摘要**: 研究评估了重组lktA蛋白作为疫苗的潜力，结果显示接种重组蛋白的牛在攻毒试验中对溶血性曼氏杆菌引起的肺炎具有显著保护作用，并诱导高水平中和抗体。
3. **《Immunogenicity of Mannheimia haemolytica recombinant leukotoxin in cattle》**
- **作者**: Dassanayake RP, et al.
- **摘要**: 通过比较不同重组lktA蛋白片段(如N端和C端)的免疫原性，发现全长重组lktA蛋白能更有效激发牛的特异性免疫应答，提示其作为亚单位疫苗的可行性。
4. **《Evaluation of a recombinant leukotoxin vaccine for bovine respiratory disease》**
- **作者**: Confer AW, et al.
- **摘要**: 在牛呼吸道疾病模型中测试了重组lktA疫苗的效力，结果显示其能显著降低肺部病变和细菌载量，证明重组蛋白在预防曼氏杆菌感染中的实用性。
(注：以上为示例性参考文献，实际文献需根据具体数据库检索确认。)
**Background of LktA Recombinant Protein**
Leukotoxin A (LktA) is a critical virulence factor produced by *Mannheimia haemolytica*, a Gram-negative bacterium responsible for bovine respiratory disease (BRD), a major economic burden in the cattle industry. LktA belongs to the repeat-in-toxin (RTX) family, characterized by glycine-rich repeats and calcium-binding motifs. It specifically targets ruminant leukocytes and alveolar epithelial cells, disrupting immune defenses by forming pores in cell membranes, leading to cell lysis and inflammation. This cytolytic activity exacerbates lung damage, contributing to the pathogenesis of pneumonic pasteurellosis.
The development of recombinant LktA (rLktA) emerged to overcome challenges in studying and utilizing the native toxin, which is hazardous to handle and difficult to purify at scale. Using genetic engineering, the *lktA* gene is cloned and expressed in heterologous systems like *Escherichia coli*, enabling safe, high-yield production. Recombinant LktA retains immunogenic epitopes while lacking cytotoxicity when inactivated, making it suitable for vaccine development.
Research on rLktA focuses on two applications: (1) as a subunit vaccine antigen to induce protective immunity against BRD, and (2) as a tool to study host-pathogen interactions and toxin mechanisms. Its structure-function insights aid in designing inhibitors or attenuated toxoids. Additionally, rLktA serves in diagnostic assays to detect *M. haemolytica* infections.
Overall, rLktA represents a safer, scalable alternative to native toxin, bridging translational research and practical solutions for controlling BRD, while advancing understanding of RTX toxin biology.
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