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Crystal structure of enoyl‐CoA hydratase from Thermus thermophilus HB8
Author(s) -
Padavattan Sivaraman,
Jos Sneha,
Gogoi Hemanga,
Bagautdinov Bagautdin
Publication year - 2021
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x21004593
Subject(s) - thermus thermophilus , random hexamer , dimer , stereochemistry , active site , chemistry , crystal structure , residue (chemistry) , enzyme , crystallography , biochemistry , organic chemistry , escherichia coli , gene
Fatty‐acid degradation is an oxidative process that involves four enzymatic steps and is referred to as the β‐oxidation pathway. During this process, long‐chain acyl‐CoAs are broken down into acetyl‐CoA, which enters the mitochondrial tricarboxylic acid (TCA) cycle, resulting in the production of energy in the form of ATP. Enoyl‐CoA hydratase (ECH) catalyzes the second step of the β‐oxidation pathway by the syn addition of water to the double bond between C2 and C3 of a 2‐ trans ‐enoyl‐CoA, resulting in the formation of a 3‐hydroxyacyl CoA. Here, the crystal structure of ECH from Thermus thermophilus HB8 ( Tt ECH) is reported at 2.85 Å resolution. Tt ECH forms a hexamer as a dimer of trimers, and wide clefts are uniquely formed between the two trimers. Although the overall structure of Tt ECH is similar to that of a hexameric ECH from Rattus norvegicus ( Rn ECH), there is a significant shift in the positions of the helices and loops around the active‐site region, which includes the replacement of a longer α3 helix with a shorter α‐helix and 3 10 ‐helix in Rn ECH. Additionally, one of the catalytic residues of Rn ECH, Glu144 (numbering based on the Rn ECH enzyme), is replaced by a glycine in Tt ECH, while the other catalytic residue Glu164, as well as Ala98 and Gly141 that stabilize the enolate intermediate, is conserved. Their putative ligand‐binding sites and active‐site residue compositions are dissimilar.