Reagents for detection and purification of antibody fragments
AssigneeDuke University
InventorsHomme W. Hellinga, David J. Sloan
Life of this patent
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Abstract
An isolated B1 domain polypeptide of bacterial Protein G which binds a Fab fragment of an IgG but substantially does not bind a Fc fragment of an IgG. Methods for the detection and purification of IgG Fc antibody fragments and Fab antibody fragments using the isolated GB1 domain polypeptides are also disclosed.
Claims30
An isolated B1 domain of protein G (GB1) polypeptide which maintains binding activity for an antigen binding (Fab) fragment of an imuunoglobulinG (IgG) but exhibits substantially no binding activity for a readily crystallized (Fc) fragment of an IgG, wherein the substantially no binding activity for a Fc fragment of an IgG is a dissociation constant for a Fc fragment of an IgG of greater than about 2 mM.
An isolated B1 domain of protein G (GB1) polypeptide which maintains binding activity for a Fab fragment of an IgG but exhibits substantially no binding activity for a Fc fragment of an IgG, wherein the substantially no binding activity for a Fc fragment of an IgG is a dissociation constant for a Fc fragment of an IgG of greater than about 2 mM, wherein said B1 domain further comprises a mutated “knobs-into-holes” binding site for a Fc fragment of an IgG wherein the “knobs-into holes” binding site comprises a knob from the GB1 domain polypeptide that protrudes into a hole on the Fc fragment or a hole on the GB1 domain polypeptide that receives a knob from the Fc fragment, wherein the knob from the GB1 domain polypeptide comprises residues E27 and K31, and the hole on the Fc fragment comprises residues I253 and S254;
- and wherein the hole on the GB1 domain polypeptide comprises residues N35, D36, D40, E42 and W43, and the knob from the Fc fragment comprises residue N434 of Brookhaven protien database accession number 1fcc.
Dependencies are inferred from the claim text.