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Impact of the 237th residue on the folding of human carbonic anhydrase II.

Wu MJ, Jiang Y, Yan YB - Int J Mol Sci (2011)

Bottom Line: Among the many mutations, the P237H mutation has been characterized to lead to a significant decrease in the activity of the enzyme and in the Gibbs free energy of folding.The FoldX theoretical calculations suggested that this residue did not significantly contribute to the overall folding of HCAII, since all mutants had small ΔΔG values (around 1 kcal/mol).The discrepancy between theoretical and experimental results suggested that caution should be taken when using the prediction methods to evaluate the details of disease-related mutations.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Bio-Resources and Eco-Environment of MOE, College of Life Science, Sichuan University, Chengdu 610064, China; E-Mail: wmj213@gmail.com.

ABSTRACT
The deficiency of human carbonic anhydrase II (HCAII) has been recognized to be associated with a disease called CAII deficiency syndrome (CADS). Among the many mutations, the P237H mutation has been characterized to lead to a significant decrease in the activity of the enzyme and in the Gibbs free energy of folding. However, sequence alignment indicated that the 237th residue of CAII is not fully conserved across all species. The FoldX theoretical calculations suggested that this residue did not significantly contribute to the overall folding of HCAII, since all mutants had small ΔΔG values (around 1 kcal/mol). The experimental determination indicated that at least three mutations affect HCAII folding significantly and the P237H mutation was the most deleterious one, suggesting that Pro237 was important to HCAII folding. The discrepancy between theoretical and experimental results suggested that caution should be taken when using the prediction methods to evaluate the details of disease-related mutations.

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The changes in the Gibbs free energy induced by mutations predicted by FoldX.
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f2-ijms-12-02797: The changes in the Gibbs free energy induced by mutations predicted by FoldX.

Mentions: As shown in Figure 2, all the mutations tested had small ΔΔG values around 1 kcal/mol, and the largest change in stability was found to be caused by the P- > I mutation with a value of 1.22 kcal/mol. These results suggest that according to the FoldX prediction, the substitution of Pro at position 237 by any of the other residues did not significantly affect HCAII stability. In other words, Pro237 contributed little to the overall stability of the protein. The large discrepancy between the experimental data (ΔΔG = 7.3 kcal/mol) and the prediction (ΔΔG = 1.03 kcal/mol) of the P237H mutation suggested that the role of Pro237 in HCAII might not be well evaluated by FoldX. In this case, it is necessary to determine the changes in Gibbs free energy by experimental methods. Five typical mutations (P237A, P237T, P237N, P237I, P237F) were chosen for further analysis by folding studies. The choice of P237A and P237T was due to the appearance of these two residues in the sequence of the other species (Figure 1). The other three mutations were chosen because according to the FoldX results shown in Figure 2, P237F was the most stable one among the mutants, while P237I and P237 N were the most unstable ones among the possible 20 natural amino acids.


Impact of the 237th residue on the folding of human carbonic anhydrase II.

Wu MJ, Jiang Y, Yan YB - Int J Mol Sci (2011)

The changes in the Gibbs free energy induced by mutations predicted by FoldX.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3116157&req=5

f2-ijms-12-02797: The changes in the Gibbs free energy induced by mutations predicted by FoldX.
Mentions: As shown in Figure 2, all the mutations tested had small ΔΔG values around 1 kcal/mol, and the largest change in stability was found to be caused by the P- > I mutation with a value of 1.22 kcal/mol. These results suggest that according to the FoldX prediction, the substitution of Pro at position 237 by any of the other residues did not significantly affect HCAII stability. In other words, Pro237 contributed little to the overall stability of the protein. The large discrepancy between the experimental data (ΔΔG = 7.3 kcal/mol) and the prediction (ΔΔG = 1.03 kcal/mol) of the P237H mutation suggested that the role of Pro237 in HCAII might not be well evaluated by FoldX. In this case, it is necessary to determine the changes in Gibbs free energy by experimental methods. Five typical mutations (P237A, P237T, P237N, P237I, P237F) were chosen for further analysis by folding studies. The choice of P237A and P237T was due to the appearance of these two residues in the sequence of the other species (Figure 1). The other three mutations were chosen because according to the FoldX results shown in Figure 2, P237F was the most stable one among the mutants, while P237I and P237 N were the most unstable ones among the possible 20 natural amino acids.

Bottom Line: Among the many mutations, the P237H mutation has been characterized to lead to a significant decrease in the activity of the enzyme and in the Gibbs free energy of folding.The FoldX theoretical calculations suggested that this residue did not significantly contribute to the overall folding of HCAII, since all mutants had small ΔΔG values (around 1 kcal/mol).The discrepancy between theoretical and experimental results suggested that caution should be taken when using the prediction methods to evaluate the details of disease-related mutations.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Bio-Resources and Eco-Environment of MOE, College of Life Science, Sichuan University, Chengdu 610064, China; E-Mail: wmj213@gmail.com.

ABSTRACT
The deficiency of human carbonic anhydrase II (HCAII) has been recognized to be associated with a disease called CAII deficiency syndrome (CADS). Among the many mutations, the P237H mutation has been characterized to lead to a significant decrease in the activity of the enzyme and in the Gibbs free energy of folding. However, sequence alignment indicated that the 237th residue of CAII is not fully conserved across all species. The FoldX theoretical calculations suggested that this residue did not significantly contribute to the overall folding of HCAII, since all mutants had small ΔΔG values (around 1 kcal/mol). The experimental determination indicated that at least three mutations affect HCAII folding significantly and the P237H mutation was the most deleterious one, suggesting that Pro237 was important to HCAII folding. The discrepancy between theoretical and experimental results suggested that caution should be taken when using the prediction methods to evaluate the details of disease-related mutations.

Show MeSH
Related in: MedlinePlus