Musto Raffaella, Brunori Maurizio, Cutruzzolà Francesca, Travaglini-Allocatelli Carlo
Dipartimento di Scienze Biochimiche "A Rossi Fanelli", Università di Roma "La Sapienza", Piazzale Aldo Moro 5, I-00185, Rome, Italy.
Biochim Biophys Acta. 2003 Feb 21;1645(2):139-45. doi: 10.1016/s1570-9639(02)00528-9.
In order to investigate the functional and structural role of modular structure in globins, we have engineered a chimeric myoglobin (ChimMb) in which the first and third exon come from the gene coding for the sperm whale Mb and the second exon from the gene coding for Aplysia limacina Mb. This ChimMb, fused to the Maltose Binding Protein (MBP) and expressed in Escherichia coli as an apoprotein, binds protoheme in a 1:1 stoichiometric ratio. Based on some functional and spectroscopic properties, we conclude that the central core of the ChimMb (which derives from A. limacina) is native-like. On the other hand, the ChimMb deprived (by proteolytic digestion) of the fused MBP displays a considerably reduced stability. These results suggest that the sperm whale A-G-H nucleus does not contribute significantly to the overall stability of the ChimMb.
为了研究模块结构在珠蛋白中的功能和结构作用，我们构建了一种嵌合肌红蛋白（ChimMb），其中第一个和第三个外显子来自抹香鲸肌红蛋白的编码基因，第二个外显子来自海兔肌红蛋白的编码基因。这种ChimMb与麦芽糖结合蛋白（MBP）融合，并作为脱辅基蛋白在大肠杆菌中表达，它以1:1的化学计量比结合原血红素。基于一些功能和光谱特性，我们得出结论，ChimMb的中央核心（源自海兔）具有类似天然的结构。另一方面，通过蛋白水解消化去除融合的MBP后的ChimMb稳定性显著降低。这些结果表明，抹香鲸的A-G-H核对于ChimMb的整体稳定性贡献不大。
