Protein thermal aggregation involves distinct regions: sequential events in the heat-induced unfolding and aggregation of hemoglobin.
Protein thermal aggregation plays a crucial role in protein science and engineering. Despite its biological importance, little is known about the mechanism and pathway(s) involved in the formation of aggregates. In this report, the sequential events occurring during thermal unfolding and aggregation process of hemoglobin were studied by two-dimensional infrared correlation spectroscopy. Analysis of the infrared spectra recorded at different temperatures suggested that hemoglobin denatured by a two-stage thermal transition. At the initial structural perturbation stage (30-44 degrees C), the fast red shift of the band from alpha-helix indicated that the native helical structures became more and more solvent-exposed as temperature increased. At the thermal unfolding stage (44-54 degrees C), the unfolding of solvent-exposed helical structures dominated the transition and was supposed to be responsible to the start of aggregation. At the thermal aggregation stage (54-70 degrees C), the transition was dominated by the formation of aggregates and the further unfolding of the buried structures. A close inspection of the sequential events occurring at different stages suggested that protein thermal aggregation involves distinct regions.
Yan
Yong-Bin
YB
Department of Biological Sciences and Biotechnology, State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua University, Beijing 100084, China. ybyan@mail.tsinghua.edu.cn
Wang
Qi
Q
He
Hua-Wei
HW
Zhou
Hai-Meng
HM
D000465:Algorithms; D001665:Binding Sites; D019281:Dimerization; D006454:Hemoglobins / Q000737:chemistry* / Q000528:radiation effects*; D006358:Hot Temperature; D011108:Polymers / Q000138:chemical synthesis / Q000528:radiation effects; D011485:Protein Binding / Q000528:radiation effects; D011487:Protein Conformation / Q000528:radiation effects; D011489:Protein Denaturation / Q000528:radiation effects; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013223:Statistics as Topic
D006454:Hemoglobins; D011108:Polymers