title: Characterization of the Binding of the Finland Trityl Radical with Bovine Serum Albumin.
abstract: Understanding the interactions of trityl radicals with proteins is required to expand their biomedical applications. In this work, we demonstrate that the Finland trityl radical CT-03 binds to bovine serum albumin (BSA) in aqueous solution. Upon binding with BSA, CT-03 exhibits a much broader electron paramagnetic resonance (EPR) signal and this line broadening can be reversed by proteolysis of the BSA. The binding induces a red-shift of the maximal UV-Vis absorbance wavelength of CT-03 around 470 nm, likely due to localization of CT-03 in the relatively hydrophobic region of the protein. The interaction between CT-03 and BSA is driven by a hydrophobic interaction with an estimated binding constant of 2.18 ×105M-1at 298 K. Furthermore, only one CT-03 is bound to each molecule of BSA and the binding site is determined to be the sub-domain IIA (Sudlow's site I). This protein binding of the trityl probe to albumin can be used to study the structure and function of albumin and also must be considered for its use as anin vivoimaging agent or spin label.
authors.affiliation: Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, China ; The Davis Heart and Lung Research Institute, the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio43210, United States.
authors.forename: Yuguang
authors.initials: Y
authors.lastname: Song
authors.affiliation: Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, China ; The Davis Heart and Lung Research Institute, the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio43210, United States.
authors.forename: Yangping
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin 300070, China.
authors.forename: Wenbo
authors.initials: W
authors.lastname: Liu
authors.affiliation: The Davis Heart and Lung Research Institute, the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio43210, United States ; Department of Pharmacology, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States.
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Villamena
authors.affiliation: The Davis Heart and Lung Research Institute, the Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio43210, United States.
authors.forename: Jay L
authors.initials: JL
authors.lastname: Zweier