A Mussel-inspired Ternary Material For Phosphoproteomics Analysis

Protein phosphorylation,a kind of important post-translational modifications,can not only reflect the body health,but also serve as a drug target.Therefore,finding the modification rules of protein phosphorylation is of great significance to the diagnosis and the discovery of drug targets.Nowadays,the bottom-up strategy has become an important method for studying phosphorylated proteomics with the help of mass spectrometry detection.Phosphopeptides have relatively low abundance,poor ionization efficiency,and incomplete phosphorylation of individual sites,so the employment of effective enrichment methods is the important premise for the MS analysis of phosphopeptides.At present,affinity chromatography enrichment strategies has drawn wide attention because of its unique superiorities,such as low-cost,universality,and negligible effect to the structural integrity of phosphoproteins /phosphopeptides.According to the specific enrichment mechanism,affinity chromatography enrichment strategies mainly include immobilized metal ion affinity chromatography(IMAC)and metal oxide affinity chromatography(MOAC).The design of simple,green and efficient phosphopeptides affinity materials has become a hotspot in the field of phosphopeptides separation and enrichment.In recent years,mussel-inspired chemistry has received extensive attention in the fields of environmental engineering and biomedicine because of its economy,high efficiency and sustainability.As a typical representative of mussel-inspired chemistry,polydopamine(PDA)can be coated on the surface of the substrate through a simple self-polymerization of dopamine.In addition to the simple preparation method and good biocompatibility,PDA coatings show strong chemical activity which could adsorb metal ions and react with amino and thiol groups through Michael addition reaction and Schiff base reaction.to endow the surface of the materials with specific adsorption capacity.Therefore,this paper has exploited the advantages of PDA to construct a feasible and efficient mussel inspired phosphopeptides affinity material.With the combination of mass spectrometry detection,the obtained phosphopeptides affinity material has been employed for the separation and analysis of phosphopeptides in the standard samples and biological samples.The specific content is as follows:1.A magnetic ternary material inspired by mussels has been designed and synthesized.Firstly,spherical magnetic nanomaterials with uniform size were synthesized by solvothermal method.Then,the PDA-PEI binary compounds were coated on the magnetic nanomaterial by the co-precipitation method.Subsequently,ferric ions were immobilized on the PDA-PEI binary composite through chelation to form the final magnetic ternary nanomaterial.Finally,the morphology,structure,crystal form,magnetism and Zeta potential value of the prepared magnetic ternary nanomaterials were characterized.2.The prepared magnetic ternary materials were employed for phosphoproteomics analysis.Specifically,the sample preparation based on magnetic ternary material was combined with MALDI-TOF MS to investigate the sensitivity,selectivity and repeatability of this method.Benefited from subtle combination of IMAC and electrostatic interaction/hydrogen bonding,the capture of phosphopeptides in complex biological samples has successfully achieved.In summary,this work reported a magnetic ternary adsorbent inspired by mussels and applied it for the enrichment of phosphopeptides in complex samples.The material possessed good physical and chemical properties and excellent phosphopeptides enrichment ability,which would show broad application prospects in the field of complex sample pretreatment of phosphopeptides.