Para-Cresyl Sulfate and BSA Conjugation for Developing Aptasensor: Spectroscopic Methods and Molecular Simulation

Abstract

Para-cresol sulfate (PCS), a protein-bound uremic toxin, is gut microbiota derived metabolite and known for its role in human physiology and pathology. After PCS formation, it goes to blood stream and interact with serum albumin with high affinity. Normally, PCS is cleared by the kidney but if it gets accumulated then leads to chronic kidney disease (CKD). Present study is an attempt to understand the nuances of interaction wherein bovine serum albumin (BSA) has been taken as model protein to understand this interaction. Absorption spectroscopy result indicated that in presence of PCS (ranging from 2 μM to 200 μM), the absorbance of BSA gradually decreased due to complex formation between them and obtained detection limit of 0.42 μM with a linearity of 0.95. Fourier transform infra-red and circular spectroscopy results demonstrated change in secondary structure of BSA upon interaction of PCS. These interaction studies reveal that PCS binds on two sites of BSA. Docking studies represent binding score of −5.6 Kcal mol−1, demarking that PCS is involved in interaction with BSA via amino acid residues, forming the stable complex. This study helps in PCS aptamers synthesis by using this conjugate, to fabricate apta-sensors for early detection of CKD.