TY - JOUR
T1 - Bovine α1-acid glycoprotein, a thermostable version of its human counterpart
T2 - Insights from Fourier transform infrared spectroscopy and in silico modelling
AU - Baldassarre, Maurizio
AU - Galeazzi, Roberta
AU - Maggiore, Beatrice
AU - Tanfani, Fabio
AU - Scirè, Andrea
PY - 2014
Y1 - 2014
N2 - α1-Acid glycoprotein (AGP) is a plasma protein and a member of the acute phase response. AGP is known to bind and carry several biologically active compounds, as well as to down-modulate the immune system activities. In this work, the structure of bovine AGP has been investigated by Fourier-Transform infrared spectroscopy. A model structure has been obtained on the basis of human AGP and refined by molecular dynamics. In spite of the similar structure, bovine AGP shows an unexpectedly higher (∼20 °C) thermostability than its human counterpart. Inspection of the model structure has pointed out the presence of 12 ionic bridges and 2 sulphur-aromatic interactions, whereas only 6 ionic bridges were detected in human AGP. The high number (9) of glutamic acid residues involved in the ionic interactions might explain the significantly decreased thermostability measured at pH 5.5 (T m ∼ 71 °C) with respect to pH 7.4 (Tm ∼ 81 °C), whereas thermostability of human AGP was only slightly affected by lowering the pH. As in human AGP and several other lipocalins, a temperature-induced molten globule state has been observed in the denaturation pathway of bovine AGP.
AB - α1-Acid glycoprotein (AGP) is a plasma protein and a member of the acute phase response. AGP is known to bind and carry several biologically active compounds, as well as to down-modulate the immune system activities. In this work, the structure of bovine AGP has been investigated by Fourier-Transform infrared spectroscopy. A model structure has been obtained on the basis of human AGP and refined by molecular dynamics. In spite of the similar structure, bovine AGP shows an unexpectedly higher (∼20 °C) thermostability than its human counterpart. Inspection of the model structure has pointed out the presence of 12 ionic bridges and 2 sulphur-aromatic interactions, whereas only 6 ionic bridges were detected in human AGP. The high number (9) of glutamic acid residues involved in the ionic interactions might explain the significantly decreased thermostability measured at pH 5.5 (T m ∼ 71 °C) with respect to pH 7.4 (Tm ∼ 81 °C), whereas thermostability of human AGP was only slightly affected by lowering the pH. As in human AGP and several other lipocalins, a temperature-induced molten globule state has been observed in the denaturation pathway of bovine AGP.
KW - FT-IR spectroscopy
KW - Lipocalins
KW - Molecular dynamics
KW - Molten globule-like state
KW - Thermostability
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U2 - 10.1016/j.biochi.2014.02.002
DO - 10.1016/j.biochi.2014.02.002
M3 - Article
C2 - 24530968
AN - SCOPUS:84901773420
VL - 102
SP - 19
EP - 28
JO - Biochimie
JF - Biochimie
SN - 0300-9084
IS - 1
ER -