We successfully designed the bilayer-capsule-formable OLE-ZIP proteins by fusing the dimeric coiled coil motif (NZ and CZ) [1] and the hydrophobic domain OLE(56–106) of the sunflower-derived oleosin. In order to improve handling in a buffer, we characterized the fusion protein with thioredoxin, Trx-OLE-ZIP as an alternative. Based on the emulsion method, Trx-OLE-ZIP could successfully form stable liposome-kind bilayer capsules, with empty hollow. Furthermore, it could encapsulate other water-soluble proteins, such as GFP, to the internal hollow with a buffer of inner aqueous phase. By mutating four conserved Thr residues (Thr⁵⁹, Thr⁶⁶, Thr⁹⁷, and Thr¹⁰⁴) in the OLE(56–106) domain with Asp residues, we further successfully constructed the pH-sensitive mutant, Trx-OLE-D-ZIP. Under weakly acidic conditions at pH = 5, Trx-OLE-D-ZIP could maintain a spherical cage-morphology. By shifting the solution pH to basic (pH = 9), the protein-cages spontaneously collapsed and released the loaded proteins.

我们通过融合向日葵衍生的油质蛋白的二聚卷曲螺旋基序（NZ和CZ）[1]和疏水域OLE（56-106），成功设计了双层胶囊可形成的OLE-ZIP蛋白。为了改善在缓冲液中的处理，我们用硫氧还蛋白（Trx-OLE-ZIP）作为替代蛋白来表征融合蛋白。基于乳液法，Trx-OLE-ZIP可以成功地形成稳定的脂质体双层胶囊，空洞。此外，它可以用内部水相缓冲液将其他水溶性蛋白（例如GFP）封装到内部空腔中。通过突变四个保守的Thr残基（Thr ⁵⁹，Thr ⁶⁶，Thr ⁹⁷和Thr ¹⁰⁴）在带有Asp残基的OLE（56–106）域中，我们进一步成功构建了对pH敏感的突变体Trx-OLE-D-ZIP。在pH = 5的弱酸性条件下，Trx-OLE-D-ZIP可以保持球形的笼形结构。通过将溶液的pH调至碱性（pH = 9），蛋白笼自发塌陷并释放出负载的蛋白。