Metal-dependent amyloid β-degrading catalytic antibody construct.
Catalytic antibodies (catabodies) that degrade target antigens rapidly are rare. We describe the metal-dependence of catabody construct 2E6, an engineered heterodimer of immunoglobulin light chain variable domains that hydrolyzes amyloid β peptides (Aβ) specifically. In addition to the electrophilic phosphonate inhibitor of serine proteases, the metal chelators ethylenediaminetetraacetic acid (EDTA) and 1,10-phenanthroline completely inhibited the hydrolysis of Aβ by catabody 2E6. Formation of catabody-electrophilic phosphonate inhibitor adducts was unaffected by EDTA, suggesting that the metal exerts a favorable effect on a catalytic step after the initial catabody nucleophilic attack on Aβ. The EDTA inactivated catabody failed to disaggregate fibrillar Aβ, indicating the functional importance of the Aβ hydrolytic activity. Treating the EDTA-inactivated catabody with Zn(2+) or Co(2+) restored the Aβ hydrolytic activity, and Zn(2+)-induced catabody conformational transitions were evident by fluorescence emission spectroscopy. The studies reveal the absolute catabody dependence on a metal cofactor.
Chemical Immunology Research Center, Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, TX 77030, USA.
Yasuhiro
Y
Nishiyama
Chemical Immunology Research Center, Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, TX 77030, USA.
Hiroaki
H
Taguchi
Chemical Immunology Research Center, Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, TX 77030, USA.
Mariko
M
Hara
Chemical Immunology Research Center, Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, TX 77030, USA.
Stephanie A
SA
Planque
Chemical Immunology Research Center, Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, TX 77030, USA.
Yukie
Y
Mitsuda
Chemical Immunology Research Center, Department of Pathology and Laboratory Medicine, University of Texas-Houston Medical School, Houston, TX 77030, USA. Electronic address: Sudhir.Paul@uth.tmc.edu.
Sudhir
S
Paul
D000544:Alzheimer Disease; D016229:Amyloid beta-Peptides / Q000737:chemistry / Q000378:metabolism*; D017151:Antibodies, Catalytic / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism*; D002614:Chelating Agents / Q000494:pharmacology; D003300:Copper / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D006801:Humans; D006868:Hydrolysis; D015032:Zinc / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology
D016229:Amyloid beta-Peptides; D017151:Antibodies, Catalytic; D002614:Chelating Agents; D003300:Copper; D004492:Edetic Acid; D015032:Zinc
Alzheimer disease; Amyloid β clearance; Catalytic antibody light chain; Metal activation