Xin Min Zhao1, Li Qiu Xia2, Xiao Ping Yang3, Xiao Yun Peng4. 1. Department of Chemistry and Environmental Engineering, Hunan City University, Yiyang 413000, Hunan, China; Key Laboratory of Microbial Molecular Biology of Hunan Province, College of Life Science, Hunan Normal University, Changsha 410081, Hunan, China. 2. Key Laboratory of Microbial Molecular Biology of Hunan Province, College of Life Science, Hunan Normal University, Changsha 410081, Hunan, China. 3. Department of Chemistry and Environmental Engineering, Hunan City University, Yiyang 413000, Hunan, China; Division of Medical Oncology, Department of Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, USA. 4. Department of Chemistry and Environmental Engineering, Hunan City University, Yiyang 413000, Hunan, China.
Abstract
OBJECTIVE: To investigate the flexibility and mobility of the Bacillus thuringiensis toxin Cry1Aa. 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 Cry1Aa network rigidity with the increase of temperature was evident. Two phase transition points in which the Cry1Aa 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.
OBJECTIVE: To investigate the flexibility and mobility of the Bacillus thuringiensis toxin Cry1Aa. 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 Cry1Aa network rigidity with the increase of temperature was evident. Two phase transition points in which the Cry1Aa 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.