ABSTRACT
To generate a library covering a relatively wide area of the chemical space, molecular descriptors, and multivariate data analysis were combined to select the building blocks required for generating a diversity optimized library of putative Fc-fragment binding ligands. In such a method of library design, structural information about the target protein is not needed. Synthesis of the resulting 770 member virtual library was carried out using encoded beads, which facilitated rapid identification of the subsequent hits. The library was screened in an on-bead fluorescence assay with immunoglobulin G Fc-fragment of the subtype 4 to identify Fc-fragment binding ligands that would be useful for purifying monoclonal antibodies. An analysis of the positions of the hits in the chemical space revealed that the ones with the highest fluorescence were primarily concentrated in a particular part of the chemical space. One of the identified hits, when immobilized on amino sepharose, was able to purify a monoclonal antibody from crude cell supernatant with purity of 84% and a 70% recovery. The chemometric tools employed for the library design allowed the identification of the fraction of the available chemical space that would be preferred for a second generation library.
Subject(s)
Immunoglobulin Fc Fragments/chemistry , Combinatorial Chemistry Techniques/classification , Combinatorial Chemistry Techniques/methods , Databases, Protein , Gas Chromatography-Mass Spectrometry , Ligands , Molecular Structure , Peptides/analysis , Proteomics/methodsABSTRACT
The synthesis of a novel high-loading polyethylene-imine resin (ULTRAMINE) is described, and its application as a scavenger resin in various acylation reactions is demonstrated. The inverse suspension polymerization technique was used for the synthesis of well-defined spherical polymer beads. Polymer beads with different cross-linking densities were synthesized according to the degree of acryloylation of the polyethylene-imine polymer. The resin was characterized by various spectroscopic techniques. The size, shape, and morphological features of the resin were demonstrated by microscopy. The resin showed excellent swelling properties in both polar and nonpolar solvents. The chemical stability of the resin in various reagents and solvents was investigated and monitored by IR spectroscopy. The mechanical stability of the beads was determined by a single-bead compressive experiment. The ULTRAMINE beads can be used as an excellent scavenger for excess acylating reagent, as demonstrated for a variety of reactions. ULTRAMINE-red resin was derived from ULTRAMINE through exhaustive reduction of the amide carbonyl groups to yield an all-amine resin.
