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Authors
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Johani, J.; Eichelberger, K.; Guskova, O.; Dunjwa, S. C.; Bolinsson, H.; Börjesdotter, A.-M.; Nilsson, L.; Jaros, D.; Rohm, H.; Lederer, A.
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Title
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Enzymatic encoding of topology in an intrinsically disordered single-chain protein
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Date
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26.05.2026
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Number
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0
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Abstract
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Controlling the three-dimensional topology of single-chain nanoparticles (SCNPs) remains a central challenge in polymer and protein chemistry, particularly for intrinsically disordered systems lacking defined secondary structure. Here, we demonstrate that selective enzymatic intramolecular cross-linking can encode topologically biased interactions in an intrinsically disordered protein (IDP), yielding compact SCNPs with reproducible cavity architecture. Using β-casein-rich sodium caseinate (βNaCn) as a model surrogate for bovine β-casein (β-Cn), microbial transglutaminase (mTGase) introduces sparse, sequence-resolved glutamine-lysine isopeptide bonds that drive reproducible chain collapse without inducing secondary structure. Analyses by size exclusion chromatography with quintuple detection (SEC-D5), cross-linking mass spectrometry (XL-MS), molecular dynamics (MD) simulations, and SEC coupled to synchrotron small-angle x-ray scattering (SEC-SAXS) converge to reveal a topology combining a stable, compact, hydrophobic core with flexible, disordered loops. These cavities are probed using Nile red (NR) fluorescence and SEC-SAXS, which together provide topology information via guest-induced density redistribution after NR capture. This work establishes that sparse enzymatic constraint installation, combined with residue-resolved cross-link mapping and orthogonal structural analysis, can encode and validate topology in a disordered single chain, thereby placing IDP-like covalent folding in direct conceptual continuity with SCNP design.
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Publisher
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Wiley
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Wikidata
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Citation
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Angewandte Chemie International Edition (2026) e3738676
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DOI
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https://doi.org/10.1002/anie.3738676
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Tags
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