Biophysical characterization of the interaction of human albumin with an anionic porphyrin

Abstract

The manuscript describes the characterization of the interaction between meso-tetrakis(p-sulfonatophenyl)porphyrin (TSPP) and human serum albumin (HSA). TSPP is a candidate for the photosensitization of structural and functional changes in proteins while HSA provides both an excellent protein model and binding and functional characteristics that could be explored in future applications of the approach. A combination of optical spectroscopic techniques (e.g., fluorescence spectroscopy, fluorescence lifetime, circular dichroism, etc.) and computational docking simulations were applied to better characterize the TSPP/HSA interaction. Recent advances have revealed that the complex formed by TSPP and HSA has become potentially relevant to biomedical applications, biomaterials research and protein photosensitized engineering. The study has determined a likely location of the binding site that places TSPP at a site that overlaps partially with the low affinity site of ibuprofen and places one of the 90%90%italicSO3− groups of the ligand in proximity of the Trp214 residue in HSA. The characterization will enable future studies aimed at photosensitizing non-native functions of HSA for biomedical and biomaterial applications.

Multi-wavelength analytical ultracentrifugation of human serum albumin complexed with porphyrin

“…The assumption is that in the 100% HSA-metal-PPX complex all the available porphyrin is already bound to the protein, thus, addition of the apo-HSA only adds free protein that cannot form further complexes with the porphyrin ligand. Previous studies have shown that metal bound protoporphyrin binds to HSA in a 1:1 ratio [15, 16]. The concentration of all solutions was adjusted with 10 mM phosphate buffer to assure that the absorbance in the analyzed wavelength range stayed below 1.0 optical density units (OD) everywhere to assure all measurements fall within the dynamic range of the instrument.…”

Emerging Organic Thermoelectric Applications from Conducting Metallopolymers

“…-18 -Metalloporphyrins are widely applied to diverse aspects, such as sensors [56,57] , water purification [58,59] , catalysis [60,61] and even biological or medical uses [62][63][64] . For the past few years, a growing number of papers have demonstrated that metallopophyrin may also be a promising choice for developing OTE materials.…”

Effects of serum albumin on the photophysical characteristics of synthetic and endogenous protoporphyrin IX

“…On the other hand, PS binding to albumins changes their photophysical characteristics ( 17 – 19 ), which can modify their efficacy in photomedical applications. Characteristics of the environment, such as pH, can affect the interaction between PSs and albumins due to changes in their charge states and/or conformations ( 20 – 25 ); therefore, the effect of pH should be taken into account.…”