Antimicrobial peptides (AMPs) are a kind of small molecular peptide that an organism produces to resist the invasion of foreign microorganisms. AMP BSN-37 is a bovine AMP that exhibits high antibacterial activity. In this paper, the optimized gene AMP BSN-37 was cloned into pCold-SUMO for fusion expression by recombinant DNA technology. The gene sequence of AMP BSN-37 was obtained by codons reverse translation, and the codons were optimized according to the codons preference of Escherichia coli (E. coli). The recombinant plasmid was constructed and identified by PCR, enzyme digestion and sequencing. Then the recombinant plasmid was transformed into BL21 E. coli to induce expression, and the IPTG concentration and time were optimized. The expressed soluble fusion protein SUMO-BSN-37 was purified by chromatography and then cleaved by SUMO proteases to release BSN-37. SDS-PAGE electrophoresis and Western blotting were used for identification. The recombinant plasmid pCold-SUMO-BSN-37 was obtained, and the fusion AMP BSN-37 was preliminarily expressed in BL21. After optimization, the optimal expression condition was 37 ℃ with 0.4 µM IPTG and 6 h incubation. Under optimal conditions, a large amount of fusion AMP BSN-37 was obtained by purification. Western blotting showed that the fusion peptide was successfully expressed and had good activity. The expressed BSN-37 showed antimicrobial activity similar to that of synthesized BSN-37. In this study, soluble expression products of AMP BSN-37 were obtained, and the problem regarding the limited source of AMP BSN-37 could be effectively solved, laying a foundation for further research on AMP BSN-37.

抗菌肽（AMPs）是生物体为抵抗外来微生物入侵而产生的一类小分子肽。AMP BSN-37 是一种牛 AMP，具有高抗菌活性。本文利用重组DNA技术将优化后的基因AMP BSN-37克隆到pCold-SUMO中进行融合表达。通过密码子反译获得AMP BSN-37的基因序列，并根据大肠杆菌(E.coli)的密码子偏好进行密码子优化。构建重组质粒，并通过PCR、酶切和测序鉴定。然后将重组质粒转化BL21大肠杆菌诱导表达，并对IPTG浓度和时间进行优化。表达的可溶性融合蛋白SUMO-BSN-37通过层析纯化，然后通过SUMO蛋白酶切割以释放BSN-37。采用SDS-PAGE电泳和Western blotting进行鉴定。获得重组质粒pCold-SUMO-BSN-37，并在BL21中初步表达融合AMP BSN-37。经优化后，最佳表达条件为37℃，0.4μM IPTG，孵育6h。在最佳条件下，纯化得到大量融合AMP BSN-37。Western blotting结果显示融合肽成功表达并具有良好的活性。表达的BSN-37表现出与合成的BSN-37相似的抗菌活性。本研究获得了AMP BSN-37的可溶性表达产物，有效解决了AMP BSN-37来源有限的问题，为AMP BSN-37的进一步研究奠定了基础。