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PDBsum entry 2qdf
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Membrane protein, protein transport
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PDB id
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2qdf
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References listed in PDB file
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Key reference
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Title
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Structure and function of an essential component of the outer membrane protein assembly machine.
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Authors
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S.Kim,
J.C.Malinverni,
P.Sliz,
T.J.Silhavy,
S.C.Harrison,
D.Kahne.
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Ref.
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Science, 2007,
317,
961-964.
[DOI no: ]
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PubMed id
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Abstract
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Integral beta-barrel proteins are found in the outer membranes of mitochondria,
chloroplasts, and Gram-negative bacteria. The machine that assembles these
proteins contains an integral membrane protein, called YaeT in Escherichia coli,
which has one or more polypeptide transport-associated (POTRA) domains. The
crystal structure of a periplasmic fragment of YaeT reveals the POTRA domain
fold and suggests a model for how POTRA domains can bind different peptide
sequences, as required for a machine that handles numerous beta-barrel protein
precursors. Analysis of POTRA domain deletions shows which are essential and
provides a view of the spatial organization of this assembly machine.
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Figure 1.
Fig. 1. Diagram of bacterial outer membrane protein (OMP)
biogenesis.
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Figure 2.
Fig. 2. Structure of YaeT. (A) Domain organization. (B) X-ray
structure of YaeT[21-351]. POTRA domains P1 to P4 are colored
yellow, green, blue, and red, respectively. The eight residues
from P5 are colored gray. The missing electron density in the P3
domain is represented by a dashed line. (C) Ribbon diagram of a
POTRA domain (P2) with side chains of the conserved residues
shown. (D) Sequence alignments of POTRA domains from selected
members of the YaeT/Omp85, Sam50, and Toc75 families, found in
Gram-negative bacteria, mitochondria, and chloroplasts or
cyanobacteria, respectively [adapted from Sánchez-Pulido
et al. (14)]. Conserved residues are highlighted (28). The
intensity of the orange color reflects the level of conservation
in physicochemical properties. (E) X-ray structure of the dimer.
The POTRA domains in one monomer are colored as in (B); the
other monomer is purple. (F) Dimer interface showing the
C-terminal residue contacts of one monomer (gray) to the P2
(light green) and P3 (light blue) domains of the other monomer.
Labels represent hydrophobic residues. L, Leu; Y, Tyr; F, Phe;
V, Val; I, Ile; T, Thr.
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The above figures are
reprinted
by permission from the AAAs:
Science
(2007,
317,
961-964)
copyright 2007.
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