3WPA: Acinetobacter sp. Tol 5 AtaA C-terminal stalk_FL fused to GCN4 adaptors (CstalkFL)

Trimeric autotransporter adhesins (TAAs) on the cell surface of Gram-negative pathogens mediate bacterial adhesion to host cells and extracellular matrix proteins. However, AtaA, a TAA in the nonpathogenic Acinetobacter sp. strain Tol 5, shows nonspecific high adhesiveness to abiotic material surfaces as well as to biotic surfaces. It consists of a passenger domain secreted by the C-terminal transmembrane anchor domain (TM), and the passenger domain contains an N-terminal head, N-terminal stalk, C-terminal head (Chead), and C-terminal stalk (Cstalk). The Chead-Cstalk-TM fragment, which is conserved in many Acinetobacter TAAs, has by itself the head-stalk-anchor architecture of a complete TAA. Here, we show the crystal structure of the Chead-Cstalk fragment, AtaA_C-terminal passenger domain (CPSD), providing the first view of several conserved TAA domains. The YadA-like head (Ylhead) of the fragment is capped by a unique structure (headCap), composed of three beta-hairpins and a connector motif; it also contains a head insert motif (HIM1) before its last inner beta-strand. The headCap, Ylhead, and HIM1 integrally form a stable Chead structure. Some of the major domains of the CPSD fragment are inherently flexible and provide bending sites for the fiber between segments whose toughness is ensured by topological chain exchange and hydrophobic core formation inside the trimer. Thus, although adherence assays using in-frame deletion mutants revealed that the characteristic adhesive sites of AtaA reside in its N-terminal part, the flexibility and toughness of the CPSD part provide the resilience that enables the adhesive properties of the full-length fiber across a wide range of conditions.
PDB ID: 3WPADownload
MMDB ID: 127378
PDB Deposition Date: 2014/1/10
Updated in MMDB: 2017/12
Experimental Method:
x-ray diffraction
Resolution: 1.79  Å
Source Organism:
Similar Structures:
Biological Unit for 3WPA: trimeric; determined by author and by software (PISA)
Molecular Components in 3WPA
Label Count Molecule
Proteins (3 molecules)
Trimeric Autotransporter Adhesin
Molecule annotation
Chemical (1 molecule)
* Click molecule labels to explore molecular sequence information.

Citing MMDB