Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
Department of Biochemistry and Molecular Biology, University of the Basque Country, P.O. Box 644, 48080 Bilbao, Spain.
Toxins (Basel). 2019 Jul 10;11(7):401. doi: 10.3390/toxins11070401.
Random mutations and selective pressure drive protein adaptation to the changing demands of the environment. As a consequence, nature favors the evolution of protein diversity. A group of proteins subject to exceptional environmental stress and known for their widespread diversity are the pore-forming hemolytic proteins from sea anemones, known as actinoporins. In this study, we identified and isolated new isoforms of actinoporins from the sea anemone (fragaceatoxins). We characterized their hemolytic activity, examined their stability and structure, and performed a comparative analysis of their primary sequence. Sequence alignment reveals that most of the variability among actinoporins is associated with non-functional residues. The differences in the thermal behavior among fragaceatoxins suggest that these variability sites contribute to changes in protein stability. In addition, the protein-protein interaction region showed a very high degree of identity (92%) within fragaceatoxins, but only 25% among all actinoporins examined, suggesting some degree of specificity at the species level. Our findings support the mechanism of evolutionary adaptation in actinoporins and reflect common pathways conducive to protein variability.
随机突变和选择压力推动蛋白质适应环境不断变化的需求。因此，大自然有利于蛋白质多样性的进化。一组受到特殊环境压力的蛋白质，以其广泛的多样性而闻名，它们是来自海葵的形成孔溶血蛋白，称为动质蛋白。在这项研究中，我们从海葵中鉴定和分离了新的动质蛋白同工型（ Fragaceatoxins ）。我们对其溶血活性进行了表征，研究了其稳定性和结构，并对其一级序列进行了比较分析。序列比对表明，动质蛋白的大部分变异性与非功能残基有关。 Fragaceatoxins 之间的热行为差异表明，这些变异位点导致蛋白质稳定性的变化。此外，蛋白-蛋白相互作用区域在 Fragaceatoxins 内具有非常高的同一性（92%），但在所有检查的动质蛋白中仅为 25%，这表明在种属水平上具有一定的特异性。我们的研究结果支持动质蛋白进化适应的机制，并反映了有利于蛋白质变异性的共同途径。
