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PDBsum entry 2wgo
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Surfactant protein
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PDB id
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2wgo
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References listed in PDB file
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Key reference
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Title
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Ranaspumin-2: structure and function of a surfactant protein from the foam nests of a tropical frog.
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Authors
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C.D.Mackenzie,
B.O.Smith,
A.Meister,
A.Blume,
X.Zhao,
J.R.Lu,
M.W.Kennedy,
A.Cooper.
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Ref.
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Biophys J, 2009,
96,
4984-4992.
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PubMed id
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Abstract
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Ranaspumin-2 (Rsn-2) is a monomeric, 11 kDa surfactant protein identified as one
of the major foam nest components of the túngara frog (Engystomops pustulosus),
with an amino acid sequence unlike any other protein described so far. We report
here on its structure in solution as determined by high-resolution NMR analysis,
together with investigations of its conformation and packing at the air-water
interface using a combination of infrared and neutron reflectivity techniques.
Despite the lack of any significant sequence similarity, Rsn-2 in solution
adopts a compact globular fold characteristic of the cystatin family, comprising
a single helix over a four-stranded sheet, in a motif not previously associated
with surfactant activity. The NMR structure of Rsn-2 shows no obvious
amphiphilicity that might be anticipated for a surfactant protein. This suggests
that it must undergo a significant conformational change when incorporated into
the air-water interface that may involve a hinge-bending, clamshell opening of
the separate helix and sheet segments to expose hydrophobic faces to air while
maintaining the highly polar surfaces in contact with the underlying water
layer. This model is supported by direct observation of the relative
orientations of secondary structure elements at the interface by infrared
reflection absorption spectroscopy, and by protein packing densities determined
from neutron reflectivity profiles.
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Secondary reference #1
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Title
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The biophysical chemistry of frog foam nest proteins
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Author
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C.D.Mackenzie.
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Ref.
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ph d thesis ...
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