Biocompatibility and therapeutic potential of glycosylated albumin artificial metalloenzymes


The ability of natural metalloproteins to prevent inactivation of their metal cofactors by biological metabolites, such as glutathione, is an area that has been largely ignored in the field of artificial metalloenzyme (ArM) development. Yet, for ArM research to transition into future therapeutic applications, biocompatibility remains a crucial component. The work presented here shows the creation of a human serum albumin-based ArM that can robustly protect the catalytic activity of a bound ruthenium metal, even in the presence of 20 mM glutathione under in vitro conditions. To exploit this biocompatibility, the concept of glycosylated artificial metalloenzymes (GArM) was developed, which is based on functionalizing ArMs with N-glycan targeting moieties. As a potential drug therapy, this study shows that ruthenium-bound GArM complexes could preferentially accumulate to varying cancer cell lines via glycan-based targeting for prodrug activation of the anticancer agent umbelliprenin using ring-closing metathesis.

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Fig. 1: Development of biocompatible ArMs.
Fig. 2: Characterization of alb–Ru complexes used in this study.
Fig. 3: Catalytic activity investigation of alb–Ru complexes for ring-closing and ene–yne cross-metathesis.
Fig. 4: Reactivity and kinetic exploration of alb–Ru complexes under GSH-containing conditions.
Fig. 5: Modelling (R)-enantiomers of Ru1–3,6 into the drug site I binding pocket of albumin (PDB:1H9Z).
Fig. 6: Development of targeting ArMs.
Fig. 7: GArM-based anticancer therapy.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.


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In memory of Professor Koji Nakanishi. The authors thank Glytech Inc. for supplying the complex N-glycans. CD spectral measurements were supported by the Molecular Structure Characterization Unit, RIKEN Center for Sustainable Resourse Science (CSRS). This work was supported financially by JSPS KAKENHI grants nos. JP16H03287, JP18K19154, JP18K14347 and JP15H05843 for Middle Molecular Strategy. This work was also performed with the support of the Russian Government Program for Competitive Growth, granted to Kazan Federal University.

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Preparation of reagents was carried out by S.E. and I.N. Reactivity and kinetic studies were performed by S.E., I.N. and K.V. Binding studies were performed by K.V. Prodrug activation and biological studies were carried out by I.N. and K.V. Modelling studies were carried out by K.V. and N.K. The manuscript was written by K.V. and K.T. and checked by M.Y. and A.K. The research was directed and supervised by K.T.

Correspondence to Katsunori Tanaka.

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Eda, S., Nasibullin, I., Vong, K. et al. Biocompatibility and therapeutic potential of glycosylated albumin artificial metalloenzymes. Nat Catal 2, 780–792 (2019) doi:10.1038/s41929-019-0317-4

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