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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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Abstract
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The bacteriocin AS-48 is a cationic peptide (7149 Da) having a broad
antimicrobial spectrum, encoded by the 68 kb conjugative plasmid pMB2 from
Enterococcus faecalis S-48. It is a unique peptide since it has a cyclic
structure, which is achieved by the formation of a tail-head peptide bond after
ribosomal synthesis (Gálvez et al., 1989; Martínez-Bueno et al., 1994; Samyn
et al., 1994). Preliminary CD and calorimetric studies (data not shown) pointed
towards a highly helical and very stable three dimensional structure. All the
information gathered until now indicates that the target of AS-48 is the
cytoplasmic membrane in which it opens channels or pores, leading to dissipation
of the proton motive force and cell death, which in some cases is also followed
by bacterial lysis (Gálvez et al., 1991). This peptide is a suitable tool for
studying protein-membrane interactions, and it also offers promising
perspectives for biotechnological applications. Knowledge of the 3D structure of
AS-48 is a first step in the conduct of further structure-function studies. Here
we report the complete 1H NMR assignment of its proton resonances together with
the resulting secondary structure pattern as prerequisites for the determination
of a high-resolution 3D solution structure.
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