Human fibroblast growth factor 7 (hFGF7) is a member of the paracrine‐acting FGF family and mediates various reactions such as wound healing, tissue homeostasis, and liver regeneration. These activities make it a plausible candidate for pharmaceutical applications as a drug. However, the low expression level and stability of the recombinant hFGF7 were known to be major hurdles for further applications. Here, the expression level and stability of hFGF7 were attempted to improve by changing the order of amino acids through circular permutation (CP), thereby expecting an alternative fate according to the N‐end rule. CP‐hFGF7 variants were constructed systematically by using putative amino acid residues in the loop region that avoided the disruption of the structural integrity especially in the functional motif. Among them, cp‐hFGF7115‐114 revealed a relatively higher expression level in the soluble fraction than the wild‐type hFGF7 and was efficiently purified (7 mg L−1) to apparent homogeneity. The activity and stability of the purified variant cp‐hFGF7115‐114 were comparable or superior to that of the wild‐type hFGF7, thereby strongly suggesting that CP could be an alternative tool for the functional expression of hFGF7 in Escherichia coli.

中文翻译：

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通过循环排列增强特性的功能变体 hFGF7 的构建和表征

人成纤维细胞生长因子 7 (hFGF7) 是具有旁分泌作用的 FGF 家族成员，介导伤口愈合、组织稳态和肝脏再生等多种反应。这些活性使其成为药物应用的合理候选者。然而，重组 hFGF7 的低表达水平和稳定性是进一步应用的主要障碍。在此，尝试通过循环排列（CP）改变氨基酸顺序来提高hFGF7的表达水平和稳定性，从而期望根据N端规则实现替代命运。 CP-hFGF7 变体是通过使用环区域中的推定氨基酸残基系统地构建的，避免了结构完整性的破坏，特别是在功能基序中。其中，cp-hFGF7115‐114显示可溶性部分中的表达水平比野生型 hFGF7 相对较高，并且被有效纯化（7 mg·L−1) 达到明显的同质性。纯化变体 cp-hFGF7 的活性和稳定性115‐114与野生型 hFGF7 相当或优于野生型 hFGF7，从而强烈表明 CP 可能是 hFGF7 功能表达的替代工具大肠杆菌。