The Cooperative Folding of Annexin A2 Relies on a Transient Non-Native Intermediate.

Fiche publication

Date publication

novembre 2022

Journal

Biophysical journal

Auteurs

Membres identifiés du Cancéropôle Est :
Dr TRAVE Gilles , Dr NOMINE Yves

Tous les auteurs :
Hollås H, Ramirez J, Nominé Y, Kostmann C, Toto A, Gianni S, Travé G, Vedeler A

Lien Pubmed

https://www.ncbi.nlm.nih.gov/pubmed/36325614

Résumé

Annexins (Anxs) are a family of highly homologous proteins that bind and aggregate lipid vesicles in the presence of calcium. All members of the family contain a variable N-terminus determining specific functions, followed by a conserved core region responsible for the general calcium-dependent lipid-binding property. The core structure consists of four homologous domains (D-D), each consisting of a right-handed super-helix of five α-helices. We present data from a combination of site-directed mutagenesis, NMR and circular dichroism showing that the G25-D34 region of the N-terminus as well as the contacts between residues D38A, R63A and Q67A of AnxA2-D are crucial for the autonomous folding and stability of D of AnxA2. However, we also show that the folding of the full-length protein is very robust in that mutations and truncations that disrupted the folding of AnxA2-D did not abolish the folding of full-length AnxA2, only lowering its thermal stability. This robustness of the folding of full-length AnxA2 is likely to be mediated by the existence of at least one transient non-native intermediate as suggested by our kinetic data using stopped flow fluorescence experiments. We also show that hydrophobic amino acids in AnxA2-D involved in interfacial contacts with AnxA2-D are important for the cooperative folding and stability of the full-length protein. Mutating all of the V57E-V98R-G101Y residues in AnxA2-D did not affect the folding of the domain, only its stability but prevented the cooperative folding of the full-length protein. Our collective results favour a highly cooperative and robust folding process mediated by alternative intermediate steps. Since AnxA2 is a multifunctional protein involved in several steps of the progression of cell transformation, these data on structure and folding pathways are therefore crucial to design anticancer drugs targeting AnxA2.