title: Assessment of new cationic porphyrin binding to plasma proteins by planar microarray and spectroscopic methods.
abstract: Porphyrins have a unique aromatic structure determining particular photochemical properties that make them promising photosensitizers for anticancer therapy. Previously, we synthesized a set of artificial porphyrins by modifying side-chain functional groups and introducing different metals into the core structure. Here, we have performed a comparative study of the binding properties of 29 cationic porphyrins with plasma proteins by using microarray and spectroscopic approaches. The porphyrins were noncovalently immobilized onto hydrogel-covered glass slides and probed to bio-conjugated human and bovine serum albumins, as well as to human hemoglobin. The signal detection was carried out at the near-infrared fluorescence wavelength (800 nm) that enabled the effect of intrinsic visible wavelength fluorescence emitted by the porphyrins tested to be discarded. Competition assays on porphyrin microarrays indicated that long-chain fatty acids (FAs) (palmitic and stearic acids) decrease porphyrin binding to both serum albumin and hemoglobin. The binding affinity of different types of cationic porphyrins for plasma proteins was quantitatively assessed in the absence and presence of FAs by fluorescent and absorption spectroscopy. Molecular docking analysis confirmed results that new porphyrins and long-chain FAs compete for the common binding site FA1 in human serum albumin and meso-substituted functional groups in porphyrins play major role in the modulation of conformational rearrangements of the protein.
authors.affiliation: Institute of Biochemistry, National Academy of Sciences of Armenia, 5/1 P. Sevak str. 0014, Yerevan, Republic of Armenia.
authors.forename: Aram
authors.initials: A
authors.lastname: Gyulkhandanyan
authors.forename: Lusine
authors.initials: L
authors.lastname: Gyulkhandanyan
authors.forename: Robert
authors.initials: R
authors.lastname: Ghazaryan
authors.forename: Fabrice
authors.initials: F
authors.lastname: Fleury
authors.forename: Marie
authors.initials: M
authors.lastname: Angelini
authors.forename: Grigor
authors.initials: G
authors.lastname: Gyulkhandanyan
authors.forename: Vehary
authors.initials: V
authors.lastname: Sakanyan
mesh_terms: D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D001798:Blood Proteins / Q000737:chemistry / Q000378:metabolism*; D002412:Cations; D002417:Cattle; D003198:Computer Simulation; D006454:Hemoglobins / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D008968:Molecular Conformation; D010169:Palmitic Acids / Q000378:metabolism / Q000494:pharmacology; D011166:Porphyrins / Q000737:chemistry / Q000378:metabolism*; D040081:Protein Array Analysis / Q000379:methods*; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013229:Stearic Acids / Q000378:metabolism / Q000494:pharmacology
chemical_list: D001798:Blood Proteins; D002412:Cations; D006454:Hemoglobins; D010169:Palmitic Acids; D011166:Porphyrins; D012709:Serum Albumin; D013229:Stearic Acids; D012710:Serum Albumin, Bovine