Photoinduced conformational changes to porphyrin-bound albumin reduces albumin binding to Osteonectin

Low intensity laser irradiation of photoactive ligands bound non-covalently to proteins can generate a structural change in the proteins, which is detectable spectroscopically. This light induced protein modification could help to study the structure/function relationship in proteins or to prompt non-native protein properties. That is, only if we can determine if and how protein function is effected. Much work has shown small light-induced secondary and tertiary structural changes to albumin have occurred when the protein is bound to a porphyrin such as protoporphyrin IX or meso-tetra(4-sulfonatophenyl)porphyrin (TSPP) and irradiated. This Affinity-Depletion study aims to explore the conformational change of TSPP-bound albumin after visible-light irradiation by testing its ability to bind the biologically relevant albumin receptor, osteonectin. Osteonectin has been covalently attached to magnetic beads, forming an affinity column, but after ten trials (of varied protocol) no substantial albumin-to-osteonectin binding could be achieved.