%A Nainy  Goel
%A Kanika  Dhiman
%A Nidhi  Kalidas
%A Anwesha  Mukhopadhyay
%A Fnu Ashish
%A Souvik Bhattacharjee
%O The copyright of this article belongs to Wiley
%J The FEBS journal
%T Plasmodium falciparum Kelch13 and its artemisinin-resistant mutants assemble as hexamers in solution: a SAXS data-driven modelling study
%X The artemisinin-resistant mutations in Plasmodium?falciparum (PfKelch13) identified worldwide are mostly confined to the Broad-complex, tramtrack and bric-?-brac/poxvirus and zinc-finger (BTB/POZ) and Kelch-repeat propeller (KRP) domains. To date, only two crystal structures of the BTB/POZ-KRP domains as tight dimers are available, which limits structure-based predictions and interpretation of its role(s) in inducing clinical artemisinin resistance. Our solution Small-Angle X-ray Scattering (SAXS) data analysis and shape restoration brought forth that: (a) PfKelch13 forms a stable hexamer in P6 symmetry, (b) interactions of the N-termini drive the hexameric assembly, and (c) the six KRP domains project independently in space, forming a cauldron-like architecture. We further deduce that the artemisinin-sensitive mutant A578S is packed like the wild-type protein, however, hexameric assemblies of the predominant artemisinin-resistant mutants R539T and C580Y displayed detectable differences in the spatial positioning of their BTB/POZ-KRP domains. Lastly, mapping of mutations known to enable artemisinin resistance suggested evolutionary pressure in the selection for mutations in the BTB/POZ-KRP domains. These mutations appear non-detrimental to the hexameric assembly of proteins, and yet somehow alter the flux of downstream events essential for the susceptibility to artemisinin.
%K artemisinin-resistance; hexamer Kelch13; Plasmodium falciparum SAXS
%D 2022
%I Wiley
%L open2976