Phosphorylation-driven conformational switching of the ArnA-ArnB complex involved in archaeal motility regulation.

ABSTRACT: ArnA and ArnB serve as regulators within the Sulfolobus archaellum regulatory network by modulating the archaellum components ArlB and ArlX, which are essential for swimming motility. Together, they form a dynamic complex that, depending on nutrient availability, exists in either a loose, unphosphorylated or a tight, phosphorylated state. This transition is directed by phosphorylation via the kinase ArnC. To investigate this transition, we determined the cocrystal structure of the ArnA/ArnB complex, revealing that the zinc finger domain of ArnA interacts with both the β-sandwich and the C-terminal domains of ArnB. HDX data support the phosphorylation-dependent transition from a loose to a tight ArnAB complex driven by sequential phosphorylation of ArnB. This modification exposes the intera

SUBMITTER: Watad M 

PROVIDER: S-EPMC12852372 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature