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PDBsum entry 1e68
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References listed in PDB file
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Key reference
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Title
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Bacteriocin as-48, A microbial cyclic polypeptide structurally and functionally related to mammalian nk-Lysin.
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Authors
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C.González,
G.M.Langdon,
M.Bruix,
A.Gálvez,
E.Valdivia,
M.Maqueda,
M.Rico.
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Ref.
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Proc Natl Acad Sci U S A, 2000,
97,
11221-11226.
[DOI no: ]
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PubMed id
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Abstract
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The solution structure of bacteriocin AS-48, a 70-residue cyclic polypeptide
from Enterococcus faecalis, consists of a globular arrangement of five
alpha-helices enclosing a compact hydrophobic core. The head-to-tail union lies
in the middle of helix 5, a fact that is shown to have a pronounced effect on
the stability of the three-dimensional structure. Positive charges in the side
chains of residues in helix 4 and in the turn linking helix 4 to helix 5 form a
cluster that most probably determine its antibacterial activity by promoting
pore formation in cell membranes. A similar five-helix structural motif has been
found in the antimicrobial NK-lysin, an effector polypeptide of T and natural
killer (NK) cells. Bacteriocin AS-48 lacks the three disulfide bridges
characteristic of the saposin fold present in NK-lysin, and has no sequence
homology with it. Nevertheless, the similar molecular architecture and high
positive charge strongly suggest a common mechanism of antibacterial action.
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Figure 1.
Fig. 1. Stereoscopic view of the superposition of the 20
best structures of bacteriocin AS-48, resulting from the DYANA
calculation. In black: superposition of backbone atoms. In red:
superposition of hydrophobic side chains at the core of the
structure. The figure was drawn with the program MOLSCRIPT.
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Figure 5.
Fig. 5. Front view (same orientation as in Fig. 4) and
back view (generated by a rotation of 180° around the z
axis) showing in cyan the hydrophobic regions at the surface of
bacteriocin AS-48.
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Secondary reference #1
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Title
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Sequence-Specific 1h assignment and secondary structure of the bacteriocin as-48 cyclic peptide.
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Authors
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G.M.Langdon,
M.Bruix,
A.Gálvez,
E.Valdivia,
M.Maqueda,
M.Rico.
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Ref.
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J Biomol Nmr, 1998,
12,
173-175.
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PubMed id
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