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Cooperative Subunit Refolding of a Light‐Harvesting Protein through a Self‐Chaperone Mechanism
Author(s) -
Laos Alistair J.,
Dean Jacob C.,
Toa Zi S. D.,
Wilk Krystyna E.,
Scholes Gregory D.,
Curmi Paul M. G.,
Thordarson Pall
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201607921
Subject(s) - chaperone (clinical) , protein quaternary structure , protein subunit , chemistry , protein folding , biophysics , chromophore , phycobiliprotein , folding (dsp implementation) , circular dichroism , biochemistry , biology , photochemistry , cyanobacteria , medicine , genetics , pathology , bacteria , electrical engineering , gene , engineering
The fold of a protein is encoded by its amino acid sequence, but how complex multimeric proteins fold and assemble into functional quaternary structures remains unclear. Here we show that two structurally different phycobiliproteins refold and reassemble in a cooperative manner from their unfolded polypeptide subunits, without biological chaperones. Refolding was confirmed by ultrafast broadband transient absorption and two‐dimensional electronic spectroscopy to probe internal chromophores as a marker of quaternary structure. Our results demonstrate a cooperative, self‐chaperone refolding mechanism, whereby the β‐subunits independently refold, thereby templating the folding of the α‐subunits, which then chaperone the assembly of the native complex, quantitatively returning all coherences. Our results indicate that subunit self‐chaperoning is a robust mechanism for heteromeric protein folding and assembly that could also be applied in self‐assembled synthetic hierarchical systems.