Architecture and regulation of an enterobacterial cellulose secretion system

Wiem Abidi (1, 2, 3) , Samira Zouhir (1, 2, 3) , Meryem Caleechurn (1) , Petya Violinova Krasteva (1, 2, 3)

1 I2BC - Institut de Biologie Intégrative de la Cellule
2 IECB - Institut Européen de Chimie et Biologie
3 CBMN - Chimie et Biologie des Membranes et des Nanoobjets

Many free-living and pathogenic enterobacteria secrete biofilm-promoting cellulose using a multicomponent, envelope-embedded Bcs secretion system under the control of intracellular second messenger c-di-GMP. The molecular understanding of system assembly and cellulose secretion has been largely limited to the crystallographic studies of a distantly homologous BcsAB synthase tandem and a low-resolution reconstruction of an assembled macrocomplex that encompasses most of the inner membrane and cytosolic subunits and features an atypical layered architecture. Here, we present cryo-EM structures of the assembled Bcs macrocomplex, as well as multiple crystallographic snapshots of regulatory Bcs subcomplexes. The structural and functional data uncover the mechanism of asymmetric secretion system assembly and periplasmic crown polymerization and reveal unexpected subunit stoichiometry, multisite c-di-GMP recognition, and ATP-dependent regulation.

Domaines: Biologie structurale [q-bio.BM]; Bactériologie

Wiem Abidi, Samira Zouhir, Meryem Caleechurn, Petya Violinova Krasteva. Architecture and regulation of an enterobacterial cellulose secretion system. Science Advances , 2021, 7 (5), pp.eabd8049. ⟨10.1126/sciadv.abd8049⟩. ⟨hal-03186797⟩