title: A new type of metal chelate affinity chromatography using trivalent lanthanide ions for phosphopeptide enrichment.
abstract: In this study, a new type of immobilized metal-ion affinity chromatography (IMAC) resin for the isolation of phosphopeptides was synthesized which is based on the specific interaction between phosphate groups and chelated lanthanide metal ions. In this regard trivalent lanthanum, holmium and erbium ions were chelated to a highly porous phosphonate polymer which was prepared by radical polymerization of vinylphosphonic acid (VPA) and divinylbenzene (DVB). The developed method was evaluated with peptide mixtures from digested standard proteins (α-casein, β-casein and ovalbumin) as well as with bovine milk, egg white and a spiked HeLa cell lysate. Compared to the commonly used TiO2 approach, the presented method showed higher selectivity for phosphorylated peptides. This can be explained by the strong preference of trivalent lanthanide ions for phosphates with which they form very tight ionic bonds. Mono- and multiply phosphorylated peptides could be enriched and released in a single basic elution step, while non-phosphorylated peptides remained on the resin. Ab initio quantum mechanical energy minimizations of model complexes for polymer-ion-ligand interactions provided geometries, binding energies and charges which are discussed in conjunction with the observed experimental properties, leading to the most satisfying agreement. The presented lanthanide-IMAC resins represent promising affinity materials for the selective isolation of phosphopeptides from biological samples.
authors.affiliation: Institute of Analytical Chemistry and Radiochemistry, Leopold-Franzens University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria.
authors.forename: Munazza R
authors.initials: MR
authors.lastname: Mirza
authors.forename: Matthias
authors.initials: M
authors.lastname: Rainer
authors.forename: Christoph B
authors.initials: CB
authors.lastname: Messner
authors.forename: Yüksel
authors.initials: Y
authors.lastname: Güzel
authors.forename: Dieter
authors.initials: D
authors.lastname: Schemeth
authors.forename: Taras
authors.initials: T
authors.lastname: Stasyk
authors.forename: Muhammad I
authors.initials: MI
authors.lastname: Choudhary
authors.forename: Lukas A
authors.initials: LA
authors.lastname: Huber
authors.forename: Bernd M
authors.initials: BM
authors.lastname: Rode
authors.forename: Günther K
authors.initials: GK
authors.lastname: Bonn
mesh_terms: D002614:Chelating Agents / Q000138:chemical synthesis / Q000737:chemistry*; D002846:Chromatography, Affinity; D007477:Ions / Q000737:chemistry; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D015394:Molecular Structure; D010316:Particle Size; D010748:Phosphopeptides / Q000302:isolation & purification*; D013499:Surface Properties
chemical_list: D002614:Chelating Agents; D007477:Ions; D028581:Lanthanoid Series Elements; D010748:Phosphopeptides