title: Conformational study of human serum albumin in pre-denaturation temperatures by differential scanning calorimetry, circular dichroism and UV spectroscopy.
abstract: Thermal conformational changes of human serum albumin (HSA) in phosphate buffer, 10 mM at pH = 7 are investigated using differential scanning calorimetric (DSC), circular dichroism (CD) and UV spectroscopic methods. The results indicate that temperature increment from 25 degrees C to 55 degrees C induces reversible conformational changes in the structure of HSA. Conformational change of HSA are shown to be a three-step process. Interestingly, melting temperature of the last domain is equal to the maximum value of fever in pathological conditions, i.e. 42 degrees C. These conformational alterations are accompanied by a mild alteration of secondary structures. Study of HSA-SDS (sodium dodecyl sulphate) interaction at 45 degrees C and 35 degrees C reveals that SDS affects the HSA structure at least in three steps: the first two steps result in more stabilization and compactness of HSA structure, while the last one induces the unfolding of HSA. Since HSA has a more affinity for SDS at 45 degrees C compared to 35 degrees C, It is suggested that the net negative charge of HSA is decreased in fever, which results in the decrease of HSA-associated cations and plasma osmolarity, and consequently, heat removal via the increase in urine volume.
authors.affiliation: Faculty of Medicine, Medical University of Ilam, Ilam, Iran. rezaei.tavirani@ibb.ut.ac.ir
authors.forename: Mostafa
authors.initials: M
authors.lastname: Rezaei Tavirani
authors.forename: Seyed Hassan
authors.initials: SH
authors.lastname: Moghaddamnia
authors.forename: Bijan
authors.initials: B
authors.lastname: Ranjbar
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Amani
authors.forename: Sayed Amir
authors.initials: SA
authors.lastname: Marashi
mesh_terms: D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D006801:Humans; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012709:Serum Albumin / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013816:Thermodynamics
chemical_list: D012709:Serum Albumin; D012967:Sodium Dodecyl Sulfate