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Deciphering the structural basis of the broad substrate specificity of myo-inositol monophosphatase (IMP) from Cicer arietinum

Authors :
Prakarsh Yadav
Bhanu Prakash Petla
Saurabh C. Saxena
Nitin Uttam Kamble
Prafull Salvi
Manoj Majee
Source :
International Journal of Biological Macromolecules. 151:967-975
Publication Year :
2020
Publisher :
Elsevier BV, 2020.

Abstract

Myo-inositol monophosphatase (IMP) is a crucial enzyme in the inositol biosynthetic pathway that dephosphorylates myo-inositol 1-phosphate and other inositol phosphate derivative compounds to maintain the homeostasis of cellular inositol pool. In our previous research, we have biochemically and functionally characterized IMP enzyme from chickpea (CaIMP), which was able to catalyze diverse substrates. We cloned, overexpressed recombinant CaIMP protein and purified it and further characterized the CaIMP with its three main substrates viz. galactose 1-P, inositol 6-P and fructose 1,6-bisP. Homology model of CaIMP was generated to elucidate the factors contributing to the broad substrate specificity of the protein. The active site of the CaIMP protein was analysed with respect to its interactions with the proposed substrates. Structural features such as, high B-factor and flexible loop regions in the active site, inspired further investigation into the static and dynamic behaviour of the active site of CaIMP protein. The electrostatic biding of each of the key substrates was assessed through molecular docking. Furthermore, molecular dynamics simulations showed that these interactions indeed were stable for extended periods of time under physiological conditions. These experiments conclusively allowed us to establish the primary factors contributing to the promiscuity in substrate binding by CaIMP protein.

Details

ISSN :
01418130
Volume :
151
Database :
OpenAIRE
Journal :
International Journal of Biological Macromolecules
Accession number :
edsair.doi.dedup.....25314c27f284282de91b8dd2dc215716
Full Text :
https://doi.org/10.1016/j.ijbiomac.2019.11.098