Department of Biology, University of Western Ontario, London, ON, N6A 5B7, Canada.
Transgenic Res. 2011 Apr;20(2):345-56. doi: 10.1007/s11248-010-9419-0. Epub 2010 Jun 18.
Soybean agglutinin (SBA) is a specific N-acetylgalactosamine-binding plant lectin that can agglutinate a wide variety of cells. SBA has great potential for medical and biotechnology-focused applications, including screening and treatment of breast cancer, isolation of fetal cells from maternal blood for genetic screening, the possibility as a carrier system for oral drug delivery, and utilization as an affinity tag for high-quality purification of tagged proteins. The success of these applications, to a large degree, critically depends on the development of a highly efficient expression system for a source of recombinant SBA (rSBA). Here, we demonstrate the utility of transient and stable expression systems in Nicotiana benthamiana and potato, respectively, for the production of rSBA, with the transgenic protein accumulated to 4% of total soluble protein (TSP) in Nicotiana benthamiana leaves and 0.3% of TSP in potato tubers. Furthermore, we show that both plant-derived rSBAs retain their ability to induce the agglutination of red blood cells, are similarly glycosylated when compared with native SBA, retained their binding specificity for N-acetylgalactosamine, and were highly resistant to degradation in simulated gastric and intestinal fluids. Affinity column purification using N-acetylgalactosamine as a specific ligand resulted in high recovery and purity of rSBA. This work is the first step toward use of rSBA for various new applications, including the development of rSBA as a novel affinity tag for simplified purification of tagged proteins and as a new carrier molecule for delivery of oral drugs.
大豆凝集素（SBA）是一种特异性的 N-乙酰半乳糖胺结合植物凝集素，能够凝集多种细胞。SBA 在医学和生物技术应用方面具有巨大的潜力，包括乳腺癌的筛选和治疗、从母体血液中分离胎儿细胞进行基因筛查、作为口服药物递送载体系统的可能性，以及作为亲和标签用于标记蛋白的高质量纯化。这些应用的成功在很大程度上取决于开发高效的重组 SBA（rSBA）来源的表达系统。在这里，我们分别在烟草和马铃薯中展示了瞬时和稳定表达系统在生产 rSBA 方面的应用，在烟草叶片中 rSBA 的积累达到总可溶性蛋白（TSP）的 4%，在马铃薯块茎中 rSBA 的积累达到 TSP 的 0.3%。此外，我们表明，两种植物来源的 rSBAs 都保留了诱导红细胞凝集的能力，与天然 SBA 相比，它们的糖基化方式相似，保留了对 N-乙酰半乳糖胺的结合特异性，并且在模拟胃液和肠液中具有很高的稳定性。使用 N-乙酰半乳糖胺作为特异性配体的亲和柱纯化导致 rSBA 的高回收率和高纯度。这项工作是将 rSBA 用于各种新应用的第一步，包括开发 rSBA 作为标记蛋白简化纯化的新型亲和标签和作为口服药物递送的新型载体分子。
