4Z9F

Halohydrin hydrogen-halide-lyase, HheA

Summary for 4Z9F

• Entry DOI: 10.2210/pdb4z9f/pdb
• Descriptor: Halohydrin epoxidase A, CHLORIDE ION (3 entities in total)
• Functional Keywords: lyase
• Biological source: Corynebacterium sp.
• Total number of polymer chains: 8
• Total formula weight: 212108.05

Authors

Watanabe, F.,Yu, F.,Ohtaki, A.,Yamanaka, Y.,Noguchi, K.,Yohda, M.,Odaka, M. (deposition date: 2015-04-10, release date: 2015-11-04, Last modification date: 2023-11-08)

Primary citation

Watanabe, F.,Yu, F.,Ohtaki, A.,Yamanaka, Y.,Noguchi, K.,Yohda, M.,Odaka, M.
Crystal structures of halohydrin hydrogen-halide-lyases from Corynebacterium sp. N-1074
Proteins, 83:2230-2239, 2015

PubMed Abstract: 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.

PubMed: 26422370
DOI: 10.1002/prot.24938

Experimental method

X-RAY DIFFRACTION (1.75 Å)