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PDBsum entry 3efc
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Membrane protein
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PDB id
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3efc
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References listed in PDB file
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Key reference
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Title
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Crystal structure of yaet: conformational flexibility and substrate recognition.
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Authors
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P.Z.Gatzeva-Topalova,
T.A.Walton,
M.C.Sousa.
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Ref.
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Structure, 2008,
16,
1873-1881.
[DOI no: ]
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PubMed id
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Abstract
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The envelope of Gram-negative bacteria consists of inner and outer membranes
surrounding the peptidoglycan wall. The outer membrane (OM) is rich in integral
membrane proteins (OMPs), which have a characteristic beta barrel domain
embedded in the OM. The Omp85 family of proteins, ubiquitous among Gram-negative
bacteria and also present in chloroplasts and mitochondria, is required for
folding and insertion of OMPs into the outer membrane. Bacterial Omp85 proteins
are characterized by a periplasmic domain containing five repeats of polypeptide
transport-associated (POTRA) motifs. Here we report the crystal structure of a
periplasmic fragment of YaeT (the Escherichia coli Omp85) containing the first
four POTRA domains in an extended conformation consistent with recent solution
X-ray scattering data. Analysis of the YaeT structure reveals conformational
flexibility around a hinge point between POTRA2 and 3 domains. The structure's
implications for substrate binding and folding mechanisms are also discussed.
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Figure 2.
Figure 2. Conformational Flexibility of the YaeT Periplasmic
Domain
(A and B) Superposition of the structure of
YaeT[21:359] presented here with that of YaeT[21:351] determined
by Kim et al. (2007) (Protein Data Bank [PDB] ID code 2QDF). The
two structures are superimposed on POTRA1 and 2 (A) or POTRA3
and 4 (B). The color scheme for YaeT[21:359] is the same as in
Figure 1. The color scheme for Kim et al.'s structure is as
follows: POTRA1, magenta; POTRA2, blue; POTRA3, dark green;
POTRA4, raspberry.
(C–E) Interfaces between POTRA domains
1 and 2 (C), 2 and 3 (D), and 3 and 4 (E). Interacting residues
are shown as sticks and secondary structure elements are shown
in cartoon representation. A semitransparent surface
representation is shown to highlight the extent of surface
interaction between the domains.
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Figure 5.
Figure 5. Comparison of the Structures of YaeT POTRA3 and
SecB
(A and B) Cartoon representations of SecB (PDB ID code
1FX3) (A) and YaeT POTRA3 (B). Aromatic residues lining the top
of a hydrophobic groove (Subsite1) are highlighted in brown-red.
Hydrophobic (but not aromatic) residues forming an extended
hydrophobic groove (Subsite2) are shown in light magenta.
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The above figures are
reprinted
from an Open Access publication published by Cell Press:
Structure
(2008,
16,
1873-1881)
copyright 2008.
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