9K2J

X-ray crystal structure of 3-hydroxyisobutyrate dehydrogenase

Summary for 9K2J

• Entry DOI: 10.2210/pdb9k2j/pdb
• Descriptor: 3-hydroxyisobutyrate dehydrogenase, SULFATE ION (2 entities in total)
• Functional Keywords: 3-hydroxyisobutyrate dehydrogenase, oxidoreductase
• Biological source: Desulfovibrio sp.
• Total number of polymer chains: 3
• Total formula weight: 91002.61

Authors

Tang, K. (deposition date: 2024-10-17, release date: 2025-03-19)

Primary citation

Ma, X.,Wang, H.,Liu, L.,Dang, H.,Tang, K.
Mirror substrates specificity of a 2, 3-dihydroxypropanesulfonate degrading enzyme in sulfate-reducing bacteria.
Int.J.Biol.Macromol., 306:141806-141806, 2025

PubMed Abstract: Ubiquitous R- and S-enantiomers of 2,3-dihydroxypropanesulfonate (DHPS), organic sulfur compounds produced by photosynthetic organisms, serve as common nutrient and energy sources for specific bacteria. While most known DHPS-degrading enzymes exhibit enantioselectivity, this study introduces a unique dehydrogenase, DhpA from the sulfate-reducing bacterium Desulfovibrio sp. DF1, capable of efficiently metabolizing both R- and S-DHPS to 3-sulfolactaldehyde (SLA). The crystal structure of DhpA reveals a conserved binding pocket that recognizes the sulfonate group of DHPS through interactions with Lys123, Ser174, and Asn175. The catalytic mechanism of the enzyme involves the oxidation of the C3-OH group of both enantiomers, facilitated by the Lys171. The mutation of Lys171 significantly diminishes activity, confirming its critical role in catalysis. Based on biochemical and genetic analyses, this study proposes a chiral DHPS degradation pathway in bacteria. This study reveals the unique enantiomeric selectivity of DhpA, expanding our understanding of the bacterial metabolism of chiral molecules.

PubMed: 40054810
DOI: 10.1016/j.ijbiomac.2025.141806

Experimental method

X-RAY DIFFRACTION (2.88 Å)