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Protein footprinting is a term used to refer to a method of biochemical analysis that investigates protein structure, assembly, and interactions within a larger macromolecular assembly. It was originally coined in reference to the use of limited proteolysis to investigate contact sites within a monoclonal antibody - protein antigen complex and a year later to examine the protection from hydroxyl radical cleavage conferred by a protein bound to DNA within a DNA-protein complex. In DNA footprinting the protein is envisioned to make an imprint (or footprint) at a particular point of interaction. This latter method was adapted through the direct treatment of proteins and their complexes with hydroxyl radicals. ==Hydroxyl radical protein footprinting== Time-resolved hydroxyl radical protein footprinting employing mass spectrometry analysis was developed in the late 1990s in synchrotron radiolysis studies. The same year, these authors reported on the use of an electrical discharge source to effect the oxidation of proteins on millisecond timescales as proteins pass from the electrosprayed solution into the mass spectrometer. These approaches have since been used to determine protein structures, protein folding, protein dynamics, and protein–protein interactions. Unlike nucleic acids, proteins oxidize rather than cleave on these timescales. Analysis of the products by mass spectrometry reveals that proteins to are oxidized in a limited manner (some 10–30% of total protein) at a number of amino acid side chains across the proteins. The rate or level of oxidation at the reactive amino acid side chains (Met, Cys, Trp, Tyr, Phe, His, Pro and Leu) provides a measure of their accessibility to the bulk solvent. The mechanisms of side chain oxidation was explored by performing the radiolysis reactions in 18O-labeled water. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Protein footprinting」の詳細全文を読む スポンサード リンク
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