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Synthetic Tuning of Domain Stoichiometry in Nanobody-Enzyme Megamolecules.

ABSTRACT: This paper presents a method to synthetically tune atomically precise megamolecule nanobody-enzyme conjugates for prodrug cancer therapy. Previous efforts to create heterobifunctional protein conjugates suffered from heterogeneity in domain stoichiometry, which in part led to the failure of antibody-enzyme conjugates in clinical trials. We used the megamolecule approach to synthesize anti-HER2 nanobody-cytosine deaminase conjugates with tunable numbers of nanobody and enzyme domains in a single, covalent molecule. Linking two nanobody domains to one enzyme domain improved avidity to a human cancer cell line by 4-fold but did not increase cytotoxicity significantly due to lowered enzyme activity. In contrast, a megamolecule composed of one nanobody and two enzyme domains resulted in an 8-fold improvement in the catalytic efficiency and increased the cytotoxic effect by over 5-fold in spheroid culture, indicating that the multimeric structure allowed for an increase in local drug activation. Our work demonstrates that the megamolecule strategy can be used to study structure-function relationships of protein conjugate therapeutics with synthetic control of protein domain stoichiometry.

SUBMITTER: Metcalf KJ

PROVIDER: S-EPMC8109025 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

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Synthetic Tuning of Domain Stoichiometry in Nanobody-Enzyme Megamolecules.

Metcalf Kevin J KJ Kimmel Blaise R BR Sykora Daniel J DJ Modica Justin A JA Parker Kelly A KA Berens Eric E Dai Raymond R Dravid Vinayak P VP Werb Zena Z Mrksich Milan M

Bioconjugate chemistry 20201210 1

This paper presents a method to synthetically tune atomically precise megamolecule nanobody-enzyme conjugates for prodrug cancer therapy. Previous efforts to create heterobifunctional protein conjugates suffered from heterogeneity in domain stoichiometry, which in part led to the failure of antibody-enzyme conjugates in clinical trials. We used the megamolecule approach to synthesize anti-HER2 nanobody-cytosine deaminase conjugates with tunable numbers of nanobody and enzyme domains in a single, ...[more]

PMID: 33301672

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Project description:Lead zirconate titanate (PZT) films with high Nb concentrations (6-13 mol%) were grown by chemical solution deposition. In concentrations up to 8 mol% Nb, the films self-compensate the stoichiometry; single phase films were grown from precursor solutions with 10 mol% PbO excess. Higher Nb concentrations induced multi-phase films unless the amount of excess PbO in the precursor solution was reduced. Phase pure perovskite films were grown with 13 mol% excess Nb with the addition of 6 mol% PbO. Charge compensation was achieved by creating lead vacancies when decreasing excess PbO level; using Kroger-Vink notation, NbTi• are ionically compensated by VPb″ to maintain charge neutrality in heavily Nb-doped PZT films. With Nb doping, films showed suppressed {100} orientation, the Curie temperature decreased, and the maximum in the relative permittivity at the phase transition broadened. The dielectric and piezoelectric properties were dramatically degraded due to increased quantity of the non-polar pyrochlore phase in multi-phase films; εr reduced from 1360 ± 8 to 940 ± 6, and the remanent d33,f value decreased from 112 to 42 pm/V when increasing the Nb concentration from 6 to 13 mol%. Property deterioration was corrected by decreasing the PbO level to 6 mol%; phase pure perovskite films were attained. εr and the remanent d33,f increased to 1330 ± 9 and 106 ± 4 pm/V, respectively. There was no discernable difference in the level of self-imprint in phase pure PZT films with Nb doping. However, the magnitude of the internal field after thermal poling at 150 °C increased significantly; the level of imprint was 30 kV/cm and 11.5 kV/cm in phase pure 6 mol% and 13 mol% Nb-doped films, respectively. The absence of mobile VO••, coupled with the immobile VPb″ in 13 mol% Nb-doped PZT films, leads to lower internal field formation upon thermal poling. For 6 mol% Nb-doped PZT films, the internal field formation was primarily governed by (1) the alignment of (VPb″-VO•• )x and (2) the injection and subsequent electron trapping by Ti4+. For 13 mol% Nb-doped PZT films, hole migration between VPb″ controlled internal field formation upon thermal poling.

Dataset Information

Synthetic Tuning of Domain Stoichiometry in Nanobody-Enzyme Megamolecules.

Publications

Synthetic Tuning of Domain Stoichiometry in Nanobody-Enzyme Megamolecules.

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