Biswas Shuvendu, Kinbara Kazushi, Oya Nobuhiro, Ishii Noriyuki, Taguchi Hideki, Aida Takuzo
Department of Chemistry and Biotechnology, School of Engineering and Center for NanoBio Integration, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
J Am Chem Soc. 2009 Jun 10;131(22):7556-7. doi: 10.1021/ja902696q.
GroEL(SP/MC), prepared by genetic and chemical modifications of group I chaperonin protein GroEL, site-specifically possesses approximately 28 photochromic (spiropyran [SP] and merocyanine [MC]) units in the entrance parts of its cavity. Addition of divalent metal ions such as Mg(2+) to a tris-HCl buffer solution of GroEL(SP/MC) results in one-dimensional (1D) assembly of GroEL(SP/MC), affording cylindrical hollow fibers with a very large aspect ratio; the longest fiber was approximately 2.5 microm long, corresponding to a 170-mer of GroEL(SP/MC) (MW approximately 1.4 x 10(8)). When such long fibers are mixed with EDTA, they are cut into short-chain oligomers and eventually into monomeric GroEL(SP/MC). Similar to GroEL, GroEL(SP/MC) possesses a large binding affinity toward denatured proteins. When GroEL(SP/MC) undergoes 1D assembly after incubation with a denatured protein, guest-containing cylindrical fibers result.
GroEL(SP/MC)是通过对I型伴侣蛋白GroEL进行基因和化学修饰制备而成，在其腔口部位位点特异性地含有大约28个光致变色（螺吡喃[SP]和部花青[MC]）单元。向GroEL(SP/MC)的三羟甲基氨基甲烷盐酸盐缓冲溶液中添加二价金属离子（如Mg(2+)）会导致GroEL(SP/MC)发生一维（1D）组装，形成具有非常大的长径比的圆柱形中空纤维；最长的纤维约2.5微米长，相当于170聚体的GroEL(SP/MC)（分子量约1.4×10(8)）。当将这种长纤维与乙二胺四乙酸混合时，它们会被切割成短链寡聚体，最终成为单体GroEL(SP/MC)。与GroEL相似，GroEL(SP/MC)对变性蛋白具有很大的结合亲和力。当GroEL(SP/MC)与变性蛋白孵育后进行1D组装时，会形成含客体的圆柱形纤维。
