Jahns Anika C, Haverkamp Richard G, Rehm Bernd H A
Institute of Molecular Biosciences, Massey University, Private Bag 11222, Palmerston North, New Zealand.
Bioconjug Chem. 2008 Oct;19(10):2072-80. doi: 10.1021/bc8001979. Epub 2008 Sep 9.
Multifunctional shell-core nano/microbeads with a hydrophobic biopolymer core and a designed protein coat for selective binding of an inorganic substance and antibodies were self-assembled inside engineered bacteria. Hybrid genes were constructed to produce tailormade bead-coating proteins in the bacterium Escherichia coli. These fusion proteins contained a binding peptide for an inorganic material, the antibody binding ZZ domain, and a self-assembly promoting as well as biopolymer synthesizing enzyme. Production of these multidomain fusion proteins inside E. coli resulted in self-assembly of beads comprising a biopolyester core and displaying covalently bound binding sites for specific and selective binding of an inorganic substance and any antibody belonging to the immunoglobulin G class. Engineered beads were isolated and purified from the respective E. coli cells by standard cell disruption procedures. Bead morphology and the binding functionalities displayed at the bead surface were assessed by the enzyme-linked immunosorbent assay, transmission electron microscopy, elemental analysis, backscattering electron density, analytical density ultracentrifugation, and atomic force microscopy. These analyses showed that bacteria can be engineered to produce fusion proteins mediating self-assembly of spherical biopolymer beads with binding affinity to gold and/or silica and antibodies. Spherical structures of this type could conceivably serve as nano/microdevices for bioimaging in medical approaches where an antibody mediated targeted delivery of an inorganic contrast agent would be desired.
具有疏水性生物聚合物核心和设计用于选择性结合无机物质和抗体的蛋白质外壳的多功能核壳纳米/微珠在工程细菌内自组装。构建杂交基因以在大肠杆菌中产生定制的珠涂层蛋白。这些融合蛋白包含用于无机材料的结合肽、抗体结合ZZ结构域以及自组装促进和生物聚合物合成酶。在大肠杆菌内产生这些多结构域融合蛋白导致珠的自组装，所述珠包含生物聚酯核心并展示用于无机物质和属于免疫球蛋白G类的任何抗体的特异性和选择性结合的共价结合位点。通过标准细胞破碎程序从相应的大肠杆菌细胞中分离和纯化工程珠。通过酶联免疫吸附测定、透射电子显微镜、元素分析、背散射电子密度、分析密度超速离心和原子力显微镜评估珠的形态和在珠表面展示的结合功能。这些分析表明，可以对细菌进行工程改造以产生介导球形生物聚合物珠自组装的融合蛋白，所述珠对金和/或二氧化硅以及抗体具有结合亲和力。这种类型的球形结构可以想象用作医学方法中生物成像的纳米/微器件，其中需要抗体介导的无机造影剂的靶向递送。
