Structural mechanism for modulation of functional amyloid and biofilm formation by Staphylococcal Bap protein switch.

ABSTRACT: The Staphylococcal Bap proteins sense environmental signals (such as pH, [Ca²⁺ ]) to build amyloid scaffold biofilm matrices via unknown mechanisms. We here report the crystal structure of the aggregation-prone region of Staphylococcus aureus Bap which adopts a dumbbell-shaped fold. The middle module (MM) connecting the N-terminal and C-terminal lobes consists of a tandem of novel double-Ca²⁺ -binding motifs involved in cooperative interaction networks, which undergoes Ca²⁺ -dependent order-disorder conformational switches. The N-terminal lobe is sufficient to mediate amyloid aggregation through liquid-liquid phase separation and maturation, and subsequent biofilm formation under acidic conditions. Such processes are promoted by disordered MM at low [Ca

SUBMITTER: Ma J 

PROVIDER: S-EPMC8280801 | biostudies-literature | 2021 Jul

REPOSITORIES: biostudies-literature