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PDBsum entry 4z9f
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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 structures of halohydrin hydrogen-Halide-Lyases from corynebacterium sp. N-1074.
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Authors
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F.Watanabe,
F.Yu,
A.Ohtaki,
Y.Yamanaka,
K.Noguchi,
M.Yohda,
M.Odaka.
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Ref.
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Proteins, 2015,
83,
2230-2239.
[DOI no: ]
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PubMed id
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Abstract
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Halohydrin hydrogen-halide-lyase (H-Lyase) is a bacterial enzyme that is
involved in the degradation of halohydrins. This enzyme catalyzes the
intramolecular nucleophilic displacement of a halogen by a vicinal hydroxyl
group in halohydrins to produce the corresponding epoxides. The epoxide products
are subsequently hydrolyzed by an epoxide hydrolase, yielding the corresponding
1, 2-diol. Until now, six different H-Lyases have been studied. These H-Lyases
are grouped into three subtypes (A, B, and C) based on amino acid sequence
similarities and exhibit different enantioselectivity. Corynebacterium sp.
strain N-1074 has two different isozymes of H-Lyase, HheA (A-type) and HheB
(B-type). We have determined their crystal structures to elucidate the
differences in enantioselectivity among them. All three groups share a similar
structure, including catalytic sites. The lack of enantioselectivity of HheA
seems to be due to the relatively wide size of the substrate tunnel compared to
that of other H-Lyases. Among the B-type H-Lyases, HheB shows relatively high
enantioselectivity compared to that of HheBGP1 . This difference seems to be due
to amino acid replacements at the active site tunnel. The binding mode of 1,
3-dicyano-2-propanol at the catalytic site in the crystal structure of the
HheB-DiCN complex suggests that the product should be (R)-epichlorohydrin, which
agrees with the enantioselectivity of HheB. Comparison with the structure of
HheC provides a clue for the difference in their enantioselectivity. Proteins
2015; 83:2230-2239. © 2015 Wiley Periodicals, Inc.
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