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PDBsum entry 1ed0
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Nmr structural determination of viscotoxin a3 from viscum album l.
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Authors
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S.Romagnoli,
R.Ugolini,
F.Fogolari,
G.Schaller,
K.Urech,
M.Giannattasio,
L.Ragona,
H.Molinari.
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Ref.
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Biochem J, 2000,
350,
569-577.
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PubMed id
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Abstract
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The high-resolution three-dimensional structure of the plant toxin viscotoxin
A3, from Viscum album L., has been determined in solution by (1)H NMR
spectroscopy at pH 3.6 and 12 degrees C (the structure has been deposited in the
Protein Data Bank under the id. code 1ED0). Experimentally derived restraints
including 734 interproton distances from nuclear Overhauser effect measurements,
22 hydrogen bonds, 32 φ angle restraints from J coupling measurements,
together with three disulphide bridge constraints were used as input in
restrained molecular dynamics, followed by minimization, using DYANA and
Discover. Backbone and heavy atom root-mean-square deviations were 0.47+/-0.11 A
(1 A=10(-10) m) and 0.85+/-0.13 A respectively. Viscotoxin A3 consists of two
alpha-helices connected by a turn and a short stretch of antiparallel
beta-sheet. This fold is similar to that found in other thionins, such as
crambin, hordothionin-alpha and -beta, phoratoxin A and purothionin-alpha and
-beta. The difference in the observed biological activity for thionins of known
structure is discussed in terms of the differences in the calculated surface
potential distribution, playing an important role in their function through
disruption of cell membranes. In addition, the possible role in DNA binding of
the helix-turn-helix motif of viscotoxin A3 is discussed.
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