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Conformational Changes and Competitive Adsorption between Serum Albumin and Hemoglobin on Bioceramic Substrates
Author(s) -
Gruian Cristina Mihaela,
Rickert Christian,
Nicklisch Sascha C. T.,
Vanea Emilia,
Steinhoff HeinzJürgen,
Simon Simion
Publication year - 2017
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201600886
Subject(s) - chemistry , protein adsorption , bioceramic , adsorption , bovine serum albumin , hemoglobin , substrate (aquarium) , vaterite , biophysics , chemical engineering , crystallography , chromatography , biochemistry , organic chemistry , calcium carbonate , aragonite , oceanography , engineering , biology , geology
Traditional methods to analyze interactions and conformational changes of proteins adsorbed onto biomaterials are limited by the protein's associations with the substrate material and the complexity of the surrounding media. We have used EPR spectroscopy in combination with site‐directed spin labeling (SDSL) to investigate single protein and competitive adsorption kinetics of horse hemoglobin (Hgb) and bovine serum albumin (BSA) on a silica–calcium–phosphate bioceramic substrate. Combined continuous wave and pulsed (DEER) EPR techniques were employed to monitor local mobility/flexibility changes within the proteins and tertiary structure dynamics upon adsorption. An alternate labeling technique was introduced to allow for specific quantification of each protein adsorbed to the bioceramic surface. We show that at buffer pH 7.4 and 4.7 the amount of adsorbed hemoglobin was increased by a factor of 4–5 compared with BSA. The tertiary structure of hemoglobin was strongly affected upon adsorption, leading to a dissociation of the tetrameric molecule into monomers or αβ dimers. When the bioceramic substrate was previously functionalized with a layer of BSA, dissociation was reduced by 71 % compared with the untreated surface, indicating a “primer” effect of BSA for better adhesion of the globular hemoglobin.