2GR8: Hia 1022-1098

Autotransporter proteins are defined by the ability to drive their own secretion across the bacterial outer membrane. The Hia autotransporter of Haemophilus influenzae belongs to the trimeric autotransporter subfamily and mediates bacterial adhesion to the respiratory epithelium. In this report, we present the crystal structure of the C-terminal end of Hia, corresponding to the entire Hia translocator domain and part of the passenger domain (residues 992-1098). This domain forms a beta-barrel with 12 transmembrane beta-strands, including four strands from each subunit. The beta-barrel has a central channel of 1.8 nm in diameter that is traversed by three N-terminal alpha-helices, one from each subunit. Mutagenesis studies demonstrate that the transmembrane portion of the three alpha-helices and the loop region between the alpha-helices and the neighboring beta-strands are essential for stability of the trimeric structure of the translocator domain, and that trimerization of the translocator domain is a prerequisite for translocator activity. Overall, this study provides important insights into the mechanism of translocation in trimeric autotransporters.
PDB ID: 2GR8Download
MMDB ID: 39423
PDB Deposition Date: 2006/4/23
Updated in MMDB: 2017/10
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 2GR8: trimeric; determined by author and by software (PISA)
Molecular Components in 2GR8
Label Count Molecule
Proteins (3 molecules)
Molecule annotation
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Citing MMDB