In:
Acta Crystallographica Section D Biological Crystallography, International Union of Crystallography (IUCr), Vol. 70, No. 6 ( 2014-06-01), p. 1779-1789
Abstract:
Outer membrane protein (OMP) biogenesis is an essential process for maintaining the bacterial cell envelope and involves the β-barrel assembly machinery (BAM) for OMP recognition, folding and assembly. In Escherichia coli this function is orchestrated by five proteins: the integral outer membrane protein BamA of the Omp85 superfamily and four associated lipoproteins. To unravel the mechanism underlying OMP folding and insertion, the structure of the E. coli BamA β-barrel and P5 domain was determined at 3 Å resolution. These data add information beyond that provided in the recently published crystal structures of BamA from Haemophilus ducreyi and Neisseria gonorrhoeae and are a valuable basis for the interpretation of pertinent functional studies. In an `open' conformation, E. coli BamA displays a significant degree of flexibility between P5 and the barrel domain, which is indicative of a multi-state function in substrate transfer. E. coli BamA is characterized by a discontinuous β-barrel with impaired β1–β16 strand interactions denoted by only two connecting hydrogen bonds and a disordered C-terminus. The 16-stranded barrel surrounds a large cavity which implies a function in OMP substrate binding and partial folding. These findings strongly support a mechanism of OMP biogenesis in which substrates are partially folded inside the barrel cavity and are subsequently released laterally into the lipid bilayer.
Type of Medium:
Online Resource
ISSN:
1399-0047
DOI:
10.1107/S1399004714007482
DOI:
10.1107/S1399004714007482/mh5121sup1.pdf
Language:
Unknown
Publisher:
International Union of Crystallography (IUCr)
Publication Date:
2014
detail.hit.zdb_id:
2020492-9
detail.hit.zdb_id:
2968623-4
Permalink