Theoretical insight into the binding affinity enhancement of serine with the uranyl ion through phosphorylation?

RSC Advances Pub Date: 2016-07-18 DOI: 10.1039/C6RA14906E

Abstract

To study the coordination modes and the binding affinities of uranyl ions with serine and phosphoserine, 1?:?1, 1?:?2 and 1?:?3 type complexes of a uranyl ion with these ligands were optimized at the B3LYP/ECP60MWB-SEG/6-311+G(d)/SMD level of theory in an aqueous solution. The analyses of the electronic energies show that the uranyl ion tends to adopt a penta-coordination mode and the binding affinity of the uranyl ion toward three functional groups follows the order of –PO42? > –COO? > –PO4H?. The changes of the Gibbs free energy (ΔGsol) for the studied reactions suggest that the uranyl ion prefers to form a 1?:?3 type complex with these ligands. Moreover, the absolute values of ΔGsol increase for the phosphorylated serine with the same type of reaction. Based on the thermodynamic results, a higher solution pH is more favorable for uranyl ion coordination with phosphoserine. This work could render theoretical insights into the specific coordination modes of uranyl ions with serine/phosphoserine under different conditions and provide useful information for further study on the interactions between actinide cations with peptides and proteins.

Graphical abstract: Theoretical insight into the binding affinity enhancement of serine with the uranyl ion through phosphorylation
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