Objective To investigate the flexibility and mobility of the Bacillus thuringiensis toxin Cry1 Aa. Methods The graph theory-based program Constraint Network Analysis and normal mode-based program NMsim were used to an...Objective To investigate the flexibility and mobility of the Bacillus thuringiensis toxin Cry1 Aa. Methods The graph theory-based program Constraint Network Analysis and normal mode-based program NMsim were used to analyze the global and local flexibility indices as well as the fluctuation of individual residues in detail. Results The decrease in Cry1 Aa network rigidity with the increase of temperature was evident. Two phase transition points in which the Cry1 Aa structure lost rigidity during the thermal simulation were identified. Two rigid clusters were found in domains I and II. Weak spots were found in C-terminal domain III. Several flexible regions were found in all three domains; the largest residue fluctuation was present in the apical loop2 of domain II. Conclusion Although several flexible regions could be found in all the three domains, the most flexible regions were in the apical loops of domain II.展开更多
研究野生型苏云金芽孢杆菌Cry1Aa和Cry1C的毒性变化发现,不同的pH不但影响这些蛋白质的毒性,而且影响它们在跨膜过程中形成孔洞的能九将 Cry1 Aa α4螺旋中的15个氨基酸突变后与BBMV结合,进行光散射分析,与野生型Cry1Aa相比较,发现有3...研究野生型苏云金芽孢杆菌Cry1Aa和Cry1C的毒性变化发现,不同的pH不但影响这些蛋白质的毒性,而且影响它们在跨膜过程中形成孔洞的能九将 Cry1 Aa α4螺旋中的15个氨基酸突变后与BBMV结合,进行光散射分析,与野生型Cry1Aa相比较,发现有3个突变体几乎完全失去毒性,7个突变体毒性明显降低,5个突变体保持野生型毒性.采用计算机模拟方法研究了苏云金芽孢杆菌Cry1Aa毒蛋白α4螺旋的三维空间结构,通过观察15个不同残基定点突变对其功能的影响,解释了突变体毒性变化的原因,说明了参与膜孔洞形成氨基酸残基对Cry1Aa昆虫毒杀性的重要作用.展开更多
基金supported by grants from the National Natural Science Foundation of China(No.30670052)863 Program of China(No.2006AA02Z187)
文摘Objective To investigate the flexibility and mobility of the Bacillus thuringiensis toxin Cry1 Aa. Methods The graph theory-based program Constraint Network Analysis and normal mode-based program NMsim were used to analyze the global and local flexibility indices as well as the fluctuation of individual residues in detail. Results The decrease in Cry1 Aa network rigidity with the increase of temperature was evident. Two phase transition points in which the Cry1 Aa structure lost rigidity during the thermal simulation were identified. Two rigid clusters were found in domains I and II. Weak spots were found in C-terminal domain III. Several flexible regions were found in all three domains; the largest residue fluctuation was present in the apical loop2 of domain II. Conclusion Although several flexible regions could be found in all the three domains, the most flexible regions were in the apical loops of domain II.
文摘研究野生型苏云金芽孢杆菌Cry1Aa和Cry1C的毒性变化发现,不同的pH不但影响这些蛋白质的毒性,而且影响它们在跨膜过程中形成孔洞的能九将 Cry1 Aa α4螺旋中的15个氨基酸突变后与BBMV结合,进行光散射分析,与野生型Cry1Aa相比较,发现有3个突变体几乎完全失去毒性,7个突变体毒性明显降低,5个突变体保持野生型毒性.采用计算机模拟方法研究了苏云金芽孢杆菌Cry1Aa毒蛋白α4螺旋的三维空间结构,通过观察15个不同残基定点突变对其功能的影响,解释了突变体毒性变化的原因,说明了参与膜孔洞形成氨基酸残基对Cry1Aa昆虫毒杀性的重要作用.
