Details

Autor(en) / Beteiligte

• McLaughlin, Lorraine S
• Haft, Rembrandt JF
• Forest, Katrina T

Titel

Structural insights into the Type II secretion nanomachine

Ist Teil von

• Current opinion in structural biology, 2012-04, Vol.22 (2), p.208-216

Ort / Verlag

England: Elsevier Ltd

Erscheinungsjahr

2012

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• [Display omitted] ► Type II secretion systems move folded proteins across the bacterial outer membrane. ► 3D structures of all major soluble domains in secretion system proteins have been solved. ► A gated outer membrane secretin allows for passage of secreted substrates. ► The secretin is connected to an energy-harvesting complex by a clamp protein. ► Specialized subunits initiate assembly of a pilus-like filament required for secretion. The Type II secretion nanomachine transports folded proteins across the outer membrane of Gram-negative bacteria. Recent X-ray crystallography, electron microscopy, and molecular modeling studies provide structural insights into three functionally and spatially connected units of this nanomachine: the cytoplasmic and inner membrane energy-harvesting complex, the periplasmic helical pseudopilus, and the outer membrane secretin. Key advances include cryo-EM reconstruction of the secretin and demonstration that it interacts with both secreted substrates and a crucial transmembrane clamp protein, plus a biochemical and structural explanation of the role of low-abundance pseudopilins in initiating pseudopilus growth. Combining structures and protein interactions, we synthesize a 3D view of the complete complex consistent with a stepwise pathway in which secretin oligomerization defines sites of nanomachine biogenesis.