Role of the disulfide bond in stabilizing and folding of the fimbrial protein DraE from uropathogenic Escherichia coli
Abstrakt
Dr fimbriae are homopolymeric adhesive organelles of uropathogenic Escherichia coli composed of DraE subunits, responsible for the attachment to host cells. These structures are characterized by enormously high stability resulting from the structural properties of an Ig-like fold of DraE. One feature of DraE and other fimbrial subunits that makes them peculiar among Ig-like domain-containing proteins is a conserved disulfide bond that joins their A and B strands. Here, we investigated how this disulfide bond affects the stability and folding/unfolding pathway of DraE. We found that the disulfide bond stabilizes self-complemented DraE (DraE-sc) by ∼50 kJ mol-1 in an exclusively thermodynamic manner, i.e. by lowering the free energy of the native state and with almost no effect on the free energy of the transition state. This finding was confirmed by experimentally determined folding and unfolding rate constants of DraE-sc and a disulfide bond-lacking DraE-sc variant. Although the folding of both proteins exhibited similar kinetics, the unfolding rate constant changed upon deletion of the disulfide bond by 10 orders of magnitude, from ∼10-17 s-1 to 10-7 s-1 Molecular simulations revealed that unfolding of the disulfide bond-lacking variant is initiated by strands A or G and that disulfide bond-mediated joining of strand A to the core strand B cooperatively stabilizes the whole protein. We also show that the disulfide bond in DraE is recognized by the DraB chaperone, indicating a mechanism that precludes the incorporation of less stable, non-oxidized DraE forms into the fimbriae.
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- Kategoria:
- Publikacja w czasopiśmie
- Typ:
- artykuł w czasopiśmie wyróżnionym w JCR
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JOURNAL OF BIOLOGICAL CHEMISTRY
nr 292,
strony 16136 - 16149,
ISSN: 0021-9258 - Język:
- angielski
- Rok wydania:
- 2017
- Opis bibliograficzny:
- Pilipczuk J., Zalewska-Piątek B., Bruździak P., Czub J., Wieczór M., Olszewski M., Wanarska M., Nowicki B., Augustin-Nowacka D., Piątek R.: Role of the disulfide bond in stabilizing and folding of the fimbrial protein DraE from uropathogenic Escherichia coli// JOURNAL OF BIOLOGICAL CHEMISTRY. -Vol. 292, nr. 39 (2017), s.16136-16149
- DOI:
- Cyfrowy identyfikator dokumentu elektronicznego (otwiera się w nowej karcie) 10.1074/jbc.m117.785477
- Weryfikacja:
- Politechnika Gdańska
wyświetlono 159 razy