Insights into the unfolding pathway and identification of thermally sensitive regions of phytase from Aspergillus niger by molecular dynamics simulations

Verfasser / Beitragende:
[Kapil Kumar, Krunal Patel, D Agrawal, J Khire]
Ort, Verlag, Jahr:
2015
Enthalten in:
Journal of Molecular Modeling, 21/6(2015-06-01), 1-13
Format:
Artikel (online)
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024 7 0 |a 10.1007/s00894-015-2696-z  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s00894-015-2696-z 
245 0 0 |a Insights into the unfolding pathway and identification of thermally sensitive regions of phytase from Aspergillus niger by molecular dynamics simulations  |h [Elektronische Daten]  |c [Kapil Kumar, Krunal Patel, D Agrawal, J Khire] 
520 3 |a Thermal stability is of great importance in the application of commercial phytases. Phytase A (PhyA) is a monomeric protein comprising twelve α-helices and ten β-sheets. Comparative molecular dynamics (MD) simulations (at 310, 350, 400, and 500K) revealed that the thermal stability of PhyA from Aspergillus niger (A. niger) is associated with its conformational rigidity. The most thermally sensitive regions were identified as loops 8 (residues 83-106), 10 (161-174), 14 (224-230), 17 (306-331), and 24 (442-444), which are present on the surface of the protein. It was observed that solvent-exposed loops denature before or show higher flexibility than buried residues. We observed that PhyA begins to unfold at loops 8 and 14, which further extends to loop 24 at the C-terminus. The intense movement of loop 8 causes the helix H2 and beta-sheet B3 to fluctuate at high temperature. The high flexibility of the H2, H10, and H12 helices at high temperature resulted in complete denaturation. The high mobility of loop 14 easily transfers to the adjacent helices H7, H8, and H9, which fluctuate and partially unfold at high temperature (500K). It was also observed that the salt bridges Asp110-Lys149, Asp205-Lys277, Asp335-Arg136, Asp416-Arg420, and Glu387-Arg400 are important influences on the structural stability but not the thermostability, as the lengths of these salt bridges did not increase with rising temperature. The salt bridges Glu125-Arg163, Asp299-Arg136, Asp266-Arg219, Asp339-Lys278, Asp335-Arg136, and Asp424-Arg428 are all important for thermostability, as the lengths of these bridges increased dramatically with increasing temperature. Here, for the first time, we have computationally identified the thermolabile regions of PhyA, and this information could be used to engineer novel thermostable phytases. Numerous homologous phytases of fungal as well as bacterial origin are known, and these homologs show high sequence similarity. Our findings could prove useful in attempts to increase the thermostability of homologous phytases via protein engineering. 
540 |a Springer-Verlag Berlin Heidelberg, 2015 
690 7 |a Phytase A  |2 nationallicence 
690 7 |a Thermostability  |2 nationallicence 
690 7 |a Molecular dynamics simulations  |2 nationallicence 
690 7 |a Conformational dynamics  |2 nationallicence 
690 7 |a Structurally weak regions  |2 nationallicence 
700 1 |a Kumar  |D Kapil  |u NCIM, Biochemical Sciences Division, Dr. Homi Bhabha Road, 411 008, Pune, India  |4 aut 
700 1 |a Patel  |D Krunal  |u Plant Tissue Culture Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, 411 008, Pune, India  |4 aut 
700 1 |a Agrawal  |D D.  |u Plant Tissue Culture Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, 411 008, Pune, India  |4 aut 
700 1 |a Khire  |D J.  |u NCIM, Biochemical Sciences Division, Dr. Homi Bhabha Road, 411 008, Pune, India  |4 aut 
773 0 |t Journal of Molecular Modeling  |d Springer Berlin Heidelberg  |g 21/6(2015-06-01), 1-13  |x 1610-2940  |q 21:6<1  |1 2015  |2 21  |o 894 
856 4 0 |u https://doi.org/10.1007/s00894-015-2696-z  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s00894-015-2696-z  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Kumar  |D Kapil  |u NCIM, Biochemical Sciences Division, Dr. Homi Bhabha Road, 411 008, Pune, India  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Patel  |D Krunal  |u Plant Tissue Culture Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, 411 008, Pune, India  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Agrawal  |D D.  |u Plant Tissue Culture Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, 411 008, Pune, India  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Khire  |D J.  |u NCIM, Biochemical Sciences Division, Dr. Homi Bhabha Road, 411 008, Pune, India  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Journal of Molecular Modeling  |d Springer Berlin Heidelberg  |g 21/6(2015-06-01), 1-13  |x 1610-2940  |q 21:6<1  |1 2015  |2 21  |o 894