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PDBsum entry 1sim
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Hydrolase(o-glycosyl)
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PDB id
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1sim
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References listed in PDB file
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Key reference
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Title
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Crystal structure of a bacterial sialidase (from salmonella typhimurium lt2) shows the same fold as an influenza virus neuraminidase.
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Authors
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S.J.Crennell,
E.F.Garman,
W.G.Laver,
E.R.Vimr,
G.L.Taylor.
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Ref.
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Proc Natl Acad Sci U S A, 1993,
90,
9852-9856.
[DOI no: ]
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PubMed id
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Note In the PDB file this reference is
annotated as "TO BE PUBLISHED".
The citation details given above were identified by an automated
search of PubMed on title and author
names, giving a
percentage match of
76%.
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Abstract
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Sialidases (EC 3.2.1.18 or neuraminidases) remove sialic acid from
sialoglycoconjugates, are widely distributed in nature, and have been implicated
in the pathogenesis of many diseases. The three-dimensional structure of
influenza virus sialidase is known, and we now report the three-dimensional
structure of a bacterial sialidase, from Salmonella typhimurium LT2, at 2.0-A
resolution and the structure of its complex with the inhibitor
2-deoxy-2,3-dehydro-N-acetylneuraminic acid at 2.2-A resolution. The viral
enzyme is a tetramer; the bacterial enzyme, a monomer. Although the monomers are
of similar size (approximately 380 residues), the sequence similarity is low
(approximately 15%). The viral enzyme contains at least eight disulfide bridges,
conserved in all strains, and binds Ca2+, which enhances activity; the bacterial
enzyme contains one disulfide and does not bind Ca2+. Comparison of the two
structures shows a remarkable similarity both in the general fold and in the
spatial arrangement of the catalytic residues. However, an rms fit of 3.1 A
between 264 C alpha atoms of the S. typhimurium enzyme and those from an
influenza A virus reflects some major differences in the fold. In common with
the viral enzyme, the bacterial enzyme active site consists of an arginine
triad, a hydrophobic pocket, and a key tyrosine and glutamic acid, but
differences in the interactions with the O4 and glycerol groups of the inhibitor
reflect differing kinetics and substrate preferences of the two enzymes. The
repeating "Asp-box" motifs observed among the nonviral sialidase
sequences occur at topologically equivalent positions on the outside of the
structure. Implications of the structure for the catalytic mechanism, evolution,
and secretion of the enzyme are discussed.
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Secondary reference #1
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Title
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Purification, Crystallization and preliminary crystallographic study of neuraminidase from vibrio cholerae and salmonella typhimurium lt2.
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Authors
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G.Taylor,
E.Vimr,
E.Garman,
G.Laver.
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Ref.
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J Mol Biol, 1992,
226,
1287-1290.
[DOI no: ]
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PubMed id
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Figure 1.
Figure 1. Electrophoretic profiles of bacterial neuram-
inidases used for crystallizations. pproximately pg of
purified recombinant V. cholerae (lane B) and
S. typhimurium LT2 (lane C) neuraminidases were
fractionated by sodium dodecyl sulphate/poyacrylamid
gel electrophoresis, 12.5% separating gel, and visualized
by staining with Coomassie brilliant blue. lectrophoresis
conditions and molecular weight markers, umbered in
kDa on the left (lane A), were as described by Hoyer et l.
(1991).
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The above figure is
reproduced from the cited reference
with permission from Elsevier
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