Structural and thermodynamic analyses of the β-to-α transformation in RfaH reveal principles of fold-switching proteins.

ABSTRACT: The two-domain protein RfaH, a paralog of the universally conserved NusG/Spt5 transcription factors, is regulated by autoinhibition coupled to the reversible conformational switch of its 60-residue C-terminal Kyrpides, Ouzounis, Woese (KOW) domain between an α-hairpin and a β-barrel. In contrast, NusG/Spt5-KOW domains only occur in the β-barrel state. To understand the principles underlying the drastic fold switch in RfaH, we elucidated the thermodynamic stability and the structural dynamics of two RfaH- and four NusG/Spt5-KOW domains by combining biophysical and structural biology methods. We find that the RfaH-KOW β-barrel is thermodynamically less stable than that of most NusG/Spt5-KOWs and we show that it is in equilibrium with a globally unfolded species, which, strikingly, contains t

SUBMITTER: Zuber PK 

PROVIDER: S-EPMC9683785 | biostudies-literature | 2022 Oct

REPOSITORIES: biostudies-literature