title: Investigating the folding pathway and substrate induced conformational changes in B. malayi Guanylate kinase.
abstract: Guanylate kinase is one of the key enzymes in nucleotide biosynthesis. The study highlights the structural and functional properties of Brugia malayi Guanylate kinase (BmGK) in the presence of chemical denaturants. An inactive, partially unfolded, dimeric intermediate was observed at 1-2M urea while GdnCl unfolding showed monomer molten globule like intermediate at 0.8-1.0M. The results also illustrate the protective role of substrates in maintaining the integrity of the enzyme. The thermo stability of protein was found to be significantly enhanced in the presence of the substrates. Furthermore, binding of the substrates, GMP and ATP to BmGK changed its GdnCl induced unfolding pattern. Docking and molecular dynamic simulation performed for native BmGK, BmGK bound to GMP and GMP+ATP showed change in the fluctuation in the region between 130 and 150 residues. Arg134 lost its interaction with GMP and Arg145 interaction shifted to ATP after 40ns simulation upon binding of ATP to BmGK-GMP complex. We, thus, propose the importance of specific rearrangements contributed by binding of substrates which participate in the overall stability of the protein. The work here emphasizes on detailed biophysical characterization of BmGK along with the significant role of substrates in modulating the structural and functional properties of BmGK.
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow, 226031, Uttar Pradesh, India.
authors.forename: Smita
authors.initials: S
authors.lastname: Gupta
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow, 226031, Uttar Pradesh, India.
authors.forename: Sunita
authors.initials: S
authors.lastname: Yadav
authors.affiliation: Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Alagappa University, Karaikudi, Tamil Nadu, India.
authors.forename: Venkatesan
authors.initials: V
authors.lastname: Suryanarayanan
authors.affiliation: Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Alagappa University, Karaikudi, Tamil Nadu, India.
authors.forename: Sanjeev K
authors.initials: SK
authors.lastname: Singh
authors.affiliation: Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow, 226031, Uttar Pradesh, India. Electronic address: jkscdri@yahoo.com.
authors.forename: Jitendra K
authors.initials: JK
authors.lastname: Saxena
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry*; D000818:Animals; D017178:Brugia malayi / Q000737:chemistry* / Q000201:enzymology; D003432:Cross-Linking Reagents / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005976:Glutaral / Q000737:chemistry; D019791:Guanidine / Q000737:chemistry; D006157:Guanosine Monophosphate / Q000737:chemistry*; D051528:Guanylate Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015801:Helminth Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D062105:Molecular Docking Simulation; D011485:Protein Binding; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014508:Urea / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D015801:Helminth Proteins; D011994:Recombinant Proteins; D006157:Guanosine Monophosphate; D000255:Adenosine Triphosphate; D014508:Urea; D051528:Guanylate Kinases; D019791:Guanidine; D005976:Glutaral
keywords: B. malayi Guanylate Kinase; BmGK; Brugia malayi Guanylate kinase; GdnCl; MS; Molten globule; NMP kinase; SEC; Size Exclusion chromatography; Unfolding; guanidine hydrochloride; molecular simulation; nucleoside monophosphate kinase