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Original Research

Molecular dynamics study to improve the substrate adsorption of Saccharomycopsis fibuligera R64 alpha-amylase by designing a new surface binding site

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Pages 1-13 | Published online: 07 Jun 2019

Figures & data

Table 1 The list of the MD system

Figure 1 Ramachandran plot of MT1–MT3.

Abbreviations: MT1, mutant 1; MT2, mutant 2; MT3, mutant 3.
Figure 1 Ramachandran plot of MT1–MT3.

Figure 2 Z-score of template and MT1–MT3.

Abbreviations: MT1, mutant 1; MT2, mutant 2; MT3, mutant 3; NMR, nuclear magnetic resonance.
Figure 2 Z-score of template and MT1–MT3.

Figure 3 Profile of RMSD throughout 100 ns of simulation. (A) RMSD backbone of the enzyme which presented in 100 frames moving average and (B) RMSD of substrate binding.

Abbreviations: RMSD, root mean square deviation; MT1, mutant 1; MT2, mutant 2; MT3, mutant 3; (+) control, A. niger α-amylase.
Figure 3 Profile of RMSD throughout 100 ns of simulation. (A) RMSD backbone of the enzyme which presented in 100 frames moving average and (B) RMSD of substrate binding.

Figure 4 Profile of RMS fluctuation throughout 100 ns of MD simulation.

Abbreviations: RMS, root mean square; MD, molecular dynamics; MT1, mutant 1; MT2, mutant 2; MT3, mutant 3; (+) control, A. niger α-amylase.
Figure 4 Profile of RMS fluctuation throughout 100 ns of MD simulation.

Figure 5 Time evolution snapshot every 20 ns and interaction around the substrate in initial position. (A), (C), and (E) show the substrate position along the simulation and the distance of the substrate from the initial position. (B), (D), and (F) show the interaction that occurred around the substrate. The yellow, pink, and green color show the MT1, MT2, and MT3, respectively. The substrate is visualized in the green stick, and the hydrogen bond in the green dashed line.

Abbreviations: MT1, mutant 1; MT2, mutant 2; MT3, mutant 3.
Figure 5 Time evolution snapshot every 20 ns and interaction around the substrate in initial position. (A), (C), and (E) show the substrate position along the simulation and the distance of the substrate from the initial position. (B), (D), and (F) show the interaction that occurred around the substrate. The yellow, pink, and green color show the MT1, MT2, and MT3, respectively. The substrate is visualized in the green stick, and the hydrogen bond in the green dashed line.

Table 3 Computed binding energy between enzyme and substrate

Figure 6 Pairwise decomposition energy between maltose and side chain of residues around the mutation points in all systems.Residue number according to PDB ID 2GVY.

Abbreviations: MT1, mutant 1; MT2, mutant 2; MT3, mutant 3; (+) control, A. niger α-amylase.
Figure 6 Pairwise decomposition energy between maltose and side chain of residues around the mutation points in all systems.Residue number according to PDB ID 2GVY.

Figure 7 Time evolution snapshot every 20 ns at the two aromatic residues of SBS. (A) positive control, (B) MT1, (C) MT2, and (D) MT3.

Abbreviations: SBS, substrate binding site; MT1, mutant 1; MT2, mutant 2; MT3, mutant 3.
Figure 7 Time evolution snapshot every 20 ns at the two aromatic residues of SBS. (A) positive control, (B) MT1, (C) MT2, and (D) MT3.

Table 2 Hydrogen bond formation between substrate and enzyme throughout 100 ns of MD simulations

Figure 8 The summary of SBS modification in MT3. The substrate is shown in green, the two key SBSs are shown in gray, and the supporting hydrophobic region, supporting loop, and supporting residues are shown in the blue, red, and yellow circles, respectively.

Abbreviations: SBS, substrate binding site; MT3, mutant 3.
Figure 8 The summary of SBS modification in MT3. The substrate is shown in green, the two key SBSs are shown in gray, and the supporting hydrophobic region, supporting loop, and supporting residues are shown in the blue, red, and yellow circles, respectively.