Yokomaku Kyoko, Akiyama Motofusa, Morita Yoshitsugu, Kihira Kiyohito, Komatsu Teruyuki
Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan.
J Mater Chem B. 2018 Apr 28;6(16):2417-2425. doi: 10.1039/c8tb00211h. Epub 2018 Mar 28.
This report describes the synthesis and structure of core-shell protein clusters comprising haemoglobin (Hb) at the centre and recombinant feline serum albumin (rFSA) at the exterior, named as haemoglobin-albumin clusters (Hb-rFSA). Specifically, we highlight their capability as an artificial O carrier that can be used as a red blood cell (RBC) substitute for cats, the most populous pet animal in the world. First, rFSA was expressed by genetic engineering using Pichia yeast. The proteins show identical features to the native FSA derived from feline plasma. Single crystals of rFSA were prepared under a microgravity environment on the international space station (ISS), from which the structure was first revealed at 3.4 Å resolution. Subsequently, bovine Hb was wrapped covalently by rFSA using an α-succinimidyl-ε-maleimide crosslinker, yielding Hb-rFSA clusters. Three rFSA entities enfolded the Hb nuclei satisfactorily, giving the protein clusters a negative surface net charge (pI = 4.7) and preventing an immunological response against anti-Hb antibodies. The O affinity was higher (P = 9 Torr) than that of the native Hb. The Hb-rFSA clusters are anticipated for use as an alternative material for RBC transfusion, and as an O therapeutic reagent that can be exploited in various veterinary medicine scenarios.
本报告描述了核壳蛋白簇的合成与结构，该蛋白簇以中心的血红蛋白（Hb）和外部的重组猫血清白蛋白（rFSA）组成，命名为血红蛋白-白蛋白簇（Hb-rFSA）。具体而言，我们强调了它们作为人工氧载体的能力，可作为世界上数量最多的宠物猫的红细胞（RBC）替代品。首先，利用毕赤酵母通过基因工程表达rFSA。这些蛋白质与源自猫血浆的天然FSA具有相同的特征。rFSA的单晶是在国际空间站（ISS）的微重力环境下制备的，首次以3.4 Å的分辨率揭示了其结构。随后，使用α-琥珀酰亚胺基-ε-马来酰亚胺交联剂将牛血红蛋白与rFSA共价包裹，得到Hb-rFSA簇。三个rFSA实体令人满意地包裹了Hb核，使蛋白质簇具有负表面净电荷（pI = 4.7），并防止了针对抗Hb抗体的免疫反应。其氧亲和力（P = 9 Torr）高于天然Hb。Hb-rFSA簇有望用作红细胞输血的替代材料，以及可用于各种兽医学场景的氧治疗试剂。
