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PDBsum entry 1nal
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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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The three-Dimensional structure of n-Acetylneuraminate lyase from escherichia coli.
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Authors
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T.Izard,
M.C.Lawrence,
R.L.Malby,
G.G.Lilley,
P.M.Colman.
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Ref.
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Structure, 1994,
2,
361-369.
[DOI no: ]
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PubMed id
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Abstract
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BACKGROUND: N-acetylneuraminate lyase catalyzes the cleavage of
N-acetylneuraminic acid (sialic acid) to form pyruvate and
N-acetyl-D-mannosamine. The enzyme plays an important role in the regulation of
sialic acid metabolism in bacteria. The reverse reaction can be exploited for
the synthesis of sialic acid and some of its derivatives. RESULTS: The structure
of the enzyme from Escherichia coli has been determined to 2.2 A resolution by
X-ray crystallography. The enzyme is shown to be a tetramer, in which each
subunit consists of an alpha/beta-barrel domain followed by a carboxy-terminal
extension of three alpha-helices. CONCLUSIONS: The active site of the enzyme is
tentatively identified as a pocket at the carboxy-terminal end of the
eight-stranded beta-barrel. Lys165 lies within this pocket and is probably the
reactive residue which forms a Schiff base intermediate with the substrate. The
sequence of N-acetylneuraminate lyase has similarities to those of
dihydrodipicolinate synthase and MosA (an enzyme implicated in rhizopine
synthesis) suggesting that these last two enzymes share a similar structure to
N-acetylneuraminate lyase.
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Figure 2.
Figure 2. Stereo Cα trace of the Neu5Ac lyase monomer, viewed
down the β -barrel axis from its carboxy-terminal end. Every
tenth Cα is labelled. Figure 2. Stereo Cα trace of the
Neu5Ac lyase monomer, viewed down the β -barrel axis from its
carboxy-terminal end. Every tenth Cα is labelled. (Figure
produced using MOLSCRIPT [[3]10].)
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Figure 3.
Figure 3. Schematic drawing of the secondary structural
elements of Neu5Ac lyase viewed down the β -barrel axis from
its carboxy- terminal end. The putative catalytic residue Lys165
(see text) is shown in ball-and-stick representation. Figure
3. Schematic drawing of the secondary structural elements of
Neu5Ac lyase viewed down the β -barrel axis from its carboxy-
terminal end. The putative catalytic residue Lys165 (see text)
is shown in ball-and-stick representation. (Figure produced
using MOLSCRIPT [[3]10].)
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The above figures are
reprinted
by permission from Cell Press:
Structure
(1994,
2,
361-369)
copyright 1994.
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