2QIH

Crystal structure of 527-665 fragment of UspA1 protein from Moraxella catarrhalis

Summary for 2QIH

• Entry DOI: 10.2210/pdb2qih/pdb
• Descriptor: protein UspA1, PHOSPHATE ION, CHLORIDE ION, ... (4 entities in total)
• Functional Keywords: trimeric; parallel alpha-helical coiled-coil, cell adhesion
• Biological source: Moraxella catarrhalis
• Total number of polymer chains: 2
• Total formula weight: 34792.64

Authors

Conners, R.,Brady, R.L. (deposition date: 2007-07-04, release date: 2008-05-20, Last modification date: 2023-08-30)

Primary citation

Conners, R.,Hill, D.J.,Borodina, E.,Agnew, C.,Daniell, S.J.,Burton, N.M.,Sessions, R.B.,Clarke, A.R.,Catto, L.E.,Lammie, D.,Wess, T.,Brady, R.L.,Virji, M.
The Moraxella adhesin UspA1 binds to its human CEACAM1 receptor by a deformable trimeric coiled-coil.
Embo J., 27:1779-1789, 2008

PubMed Abstract: Moraxella catarrhalis is a ubiquitous human-specific bacterium commonly associated with upper and lower respiratory tract infections, including otitis media, sinusitis and chronic obstructive pulmonary disease. The bacterium uses an autotransporter protein UspA1 to target an important human cellular receptor carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1). Using X-ray crystallography, we show that the CEACAM1 receptor-binding region of UspA1 unusually consists of an extended, rod-like left-handed trimeric coiled-coil. Mutagenesis and binding studies of UspA1 and the N-domain of CEACAM1 have been used to delineate the interacting surfaces between ligand and receptor and guide assembly of the complex. However, solution scattering, molecular modelling and electron microscopy analyses all indicate that significant bending of the UspA1 coiled-coil stalk also occurs. This explains how UspA1 can engage CEACAM1 at a site far distant from its head group, permitting closer proximity of the respective cell surfaces during infection.

PubMed: 18497748
DOI: 10.1038/emboj.2008.101

Experimental method

X-RAY DIFFRACTION (1.897 Å)