Metalloantibodies.
A metalloantibody has been constructed with a coordination site for metals in the antigen binding pocket. The Zn(II) binding site from carbonic anhydrase B was used as a model. Three histidine residues have been placed in the light chain complementarity determining regions of a single chain antibody molecule. In contrast to the native protein, the mutant displayed metal-dependent fluorescence-quenching behavior. This response was interpreted as evidence for metal binding in the three-histidine site with relative affinities in the order Cu(II) greater than Zn(II) greater than Cd(II). The presence of metal cofactors in immunoglobulins should facilitate antibody catalysis of redox and hydrolytic reactions.
Iverson
B L
BL
Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, CA 92037.
Iverson
S A
SA
Roberts
V A
VA
Getzoff
E D
ED
Tainer
J A
JA
Benkovic
S J
SJ
Lerner
R A
RA
D000595:Amino Acid Sequence; D001666:Binding Sites, Antibody; D002104:Cadmium; D002256:Carbonic Anhydrases / Q000276:immunology*; D003300:Copper; D005452:Fluoresceins; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D008024:Ligands; D008670:Metals; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence; D015032:Zinc
D005452:Fluoresceins; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D008024:Ligands; D008670:Metals; D002104:Cadmium; D003300:Copper; D002256:Carbonic Anhydrases; D015032:Zinc