title: Urea-induced denaturation of human calcium/calmodulin-dependent protein kinase IV: a combined spectroscopic and MD simulation studies.
abstract: Calcium/calmodulin-dependent protein kinase IV (CaMKIV) is a multifunctional enzyme which belongs to the Ser/Thr kinase family. CaMKIV plays important role in varieties of biological processes such as gene expression regulation, memory consolidation, bone growth, T-cell maturation, sperm motility, regulation of microtubule dynamics, cell-cycle progression, and apoptosis. To measure stability parameters, urea-induced denaturation of CaMKIV was carried out at pH 7.4 and 25°C, using three different probes, namely far-UV CD, near-UV absorption, and tryptophan fluorescence. A coincidence of normalized denaturation curves of these optical properties suggests that urea-induced denaturation is a two-state process. Analysis of these denaturation curves gave values of 4.20 ± 0.12 kcal mol-1, 2.95 ± 0.15 M, and 1.42 ± 0.06 kcal mol-1M-1for [Formula: see text] (Gibbs free energy change (ΔGD) in the absence of urea), Cm(molar urea concentration ([urea]) at the midpoint of the denaturation curve), and m (=∂ΔGD/∂[urea]), respectively. All these experimental observations have been fully supported by 30 ns molecular dynamics simulation studies.
authors.affiliation: a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India.
authors.forename: Huma
authors.initials: H
authors.lastname: Naz
authors.affiliation: b Department of Chemistry , Durban University of Technology , Durban 4000 , South Africa.
authors.forename: Mohd
authors.initials: M
authors.lastname: Shahbaaz
authors.affiliation: a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India.
authors.forename: Md Anzarul
authors.initials: MA
authors.lastname: Haque
authors.affiliation: b Department of Chemistry , Durban University of Technology , Durban 4000 , South Africa.
authors.forename: Krishna
authors.initials: K
authors.lastname: Bisetty
authors.affiliation: a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India.
authors.forename: Asimul
authors.initials: A
authors.lastname: Islam
authors.affiliation: a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India.
authors.forename: Faizan
authors.initials: F
authors.lastname: Ahmad
authors.affiliation: a Center for Interdisciplinary Research in Basic Sciences , Jamia Millia Islamia , Jamia Nagar, New Delhi 110025 , India.
authors.forename: Md Imtaiyaz
authors.initials: MI
authors.lastname: Hassan
mesh_terms: D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4 / Q000737:chemistry*; D002942:Circular Dichroism; D006801:Humans; D056004:Molecular Dynamics Simulation; D011487:Protein Conformation; D011489:Protein Denaturation / Q000187:drug effects; D013057:Spectrum Analysis; D013329:Structure-Activity Relationship; D014508:Urea / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D014508:Urea; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4
keywords: calcium/calmodulin-dependent protein kinase IV; isothermal denaturation; protein folding; protein stability; two-state unfolding