TY - JOUR
T1 - GdmCl-induced unfolding studies of human carbonic anhydrase IX
T2 - a combined spectroscopic and MD simulation approach
AU - Prakash, Amresh
AU - Idrees, Danish
AU - Haque, Md Anzarul
AU - Islam, Asimul
AU - Ahmad, Faizan
AU - Hassan, Md Imtaiyaz
N1 - Publisher Copyright:
© 2016 Informa UK Limited, trading as Taylor & Francis Group.
PY - 2017/4/26
Y1 - 2017/4/26
N2 - Carbonic anhydrase IX (CAIX) is a transmembrane glycoprotein, associated with tumor, acidification which leads to the cancer, and is considered as a potential biomarker for hypoxia-induced cancers. The overexpression of CAIX is linked with hypoxia condition which is mediated by the transcription of hypoxia-induced factor (HIF-1). To understand the biophysical properties of CAIX, we have carried out a reversible isothermal denaturation of CAIX-induced by GdmCl at pH 8.0 and 25°C. Three different spectroscopic probes, the far-UV CD at 222 nm ([θ]222), Trp fluorescence emission at 342 nm (F342) and difference molar absorption coefficient at 287 nm (Δε287) were used to estimate stability parameters, Δ GD0 (Gibbs free energy change in the absence of GdmCl; Cm (midpoint of the denaturation curve), i.e. molar GdmCl concentration ([GdmCl]) at which ΔGD = 0; and m, the slope (=∂ΔGD/∂[GdmCl])). GdmCl induces a reversible denaturation of CAIX. Coincidence of the normalized transition curves of all optical properties suggests that unfolding/refolding of CAIX is a two-state process. We further performed molecular dynamics simulation of CAIX for 40 ns to see the dynamics of protein structure in different GdmCl concentrations. An excellent agreement was observed between in silico and in vitro studies.
AB - Carbonic anhydrase IX (CAIX) is a transmembrane glycoprotein, associated with tumor, acidification which leads to the cancer, and is considered as a potential biomarker for hypoxia-induced cancers. The overexpression of CAIX is linked with hypoxia condition which is mediated by the transcription of hypoxia-induced factor (HIF-1). To understand the biophysical properties of CAIX, we have carried out a reversible isothermal denaturation of CAIX-induced by GdmCl at pH 8.0 and 25°C. Three different spectroscopic probes, the far-UV CD at 222 nm ([θ]222), Trp fluorescence emission at 342 nm (F342) and difference molar absorption coefficient at 287 nm (Δε287) were used to estimate stability parameters, Δ GD0 (Gibbs free energy change in the absence of GdmCl; Cm (midpoint of the denaturation curve), i.e. molar GdmCl concentration ([GdmCl]) at which ΔGD = 0; and m, the slope (=∂ΔGD/∂[GdmCl])). GdmCl induces a reversible denaturation of CAIX. Coincidence of the normalized transition curves of all optical properties suggests that unfolding/refolding of CAIX is a two-state process. We further performed molecular dynamics simulation of CAIX for 40 ns to see the dynamics of protein structure in different GdmCl concentrations. An excellent agreement was observed between in silico and in vitro studies.
KW - GdmCl-induced denaturation
KW - human carbonic anhydrase IX
KW - molecular dynamics simulation
KW - protein stability
KW - proteinfolding
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U2 - 10.1080/07391102.2016.1179596
DO - 10.1080/07391102.2016.1179596
M3 - Article
C2 - 27092977
AN - SCOPUS:84970027831
SN - 0739-1102
VL - 35
SP - 1295
EP - 1306
JO - Journal of Biomolecular Structure and Dynamics
JF - Journal of Biomolecular Structure and Dynamics
IS - 6
ER -