Instituto de Ciências Exatas - Universidade Federal do Sul e Sudeste do Pará, Brazil.
Instituto de Química de São Carlos - Universidade de São Paulo, Brazil.
Int J Biol Macromol. 2019 Jul 15;133:30-36. doi: 10.1016/j.ijbiomac.2019.04.072. Epub 2019 Apr 12.
Glossoscolex paulistus hemoglobin structure is composed of 144 globin chains and 36 polypeptide chains lacking the heme group, with a total molecular mass of 3600 kDa. The current study focuses on the oxy-HbGp oligomeric stability, as a function of the storage time, at pH 7.0, using dynamic light scattering, analytical ultracentrifugation (AUC), optical absorption and size exclusion chromatography (SEC). HbGp stored in Tris-HCl buffer, pH 7.0, at 4 °C, for two years remains in the native form, while 4-6 years HbGp stocks present typical hemichrome species absorption spectra. AUC and SEC analyses show that the contribution of HbGp-subunits, such as, dodecamer (abcd), tetramer abcd, trimer abc and monomer d, increases with the protein aging due to the lower stability of the HbGp with the time. The dissociation and the oxidation of the iron noted for the older protein solutions indicate that HbGp storage for periods of time longer than two years changes its ability to carry oxygen. Despite the reduction of HbGp stability and oxygen carrying capacity with aging, the protein stability is still larger as compared to mammalian hemoglobins. Thus, the extracellular hemoglobins are quite stable and resistant to the auto-oxidation process, making them of interest for biotechnological applications.
胶舌螺血红蛋白的结构由 144 条球蛋白链和 36 条缺乏血红素基团的多肽链组成，总分子量为 3600 kDa。本研究主要关注氧合-HbGp 寡聚体的稳定性，作为储存时间的函数，在 pH 7.0 下使用动态光散射、分析超速离心 (AUC)、光吸收和尺寸排阻色谱 (SEC)。储存在 Tris-HCl 缓冲液中的 HbGp 在 4°C 下可保持两年仍处于天然状态，而 4-6 年的 HbGp 库存则呈现出典型的亚铁血红素物种吸收光谱。AUC 和 SEC 分析表明，由于 HbGp 随时间的稳定性降低，HbGp 亚基（如 abcd 十二聚体、abcd 四聚体、abc 三聚体和 d 单体）的贡献增加。由于铁的解离和氧化，较老的蛋白质溶液表明 HbGp 的储存时间超过两年会改变其携带氧气的能力。尽管随着老化，HbGp 的稳定性和携氧能力降低，但与哺乳动物血红蛋白相比，该蛋白的稳定性仍然较大。因此，细胞外血红蛋白非常稳定，并且能够抵抗自动氧化过程，这使得它们在生物技术应用中具有吸引力。
