8P84

X-ray structure of Thermoanaerobacterales bacterium monoamine oxidase

Summary for 8P84

• Entry DOI: 10.2210/pdb8p84/pdb
• Descriptor: Monoamine oxidase, FLAVIN-ADENINE DINUCLEOTIDE, GLYCEROL, ... (5 entities in total)
• Functional Keywords: monoamine oxidase, thermoanaerobacterales bacterium, enzyme, n-hexylamine, flavoprotein
• Biological source: Thermoanaerobacterales bacterium
• Total number of polymer chains: 2
• Total formula weight: 101915.65

Authors

Basile, L.,Santema, L.L.,Fraaije, M.W.,Binda, C. (deposition date: 2023-05-31, release date: 2023-10-18, Last modification date: 2024-11-13)

Primary citation

Santema, L.L.,Basile, L.,Binda, C.,Fraaije, M.W.
Discovery and structural characterization of a thermostable bacterial monoamine oxidase.
Febs J., 291:849-864, 2024

PubMed Abstract: Monoamine oxidases (MAOs) are pivotal regulators of neurotransmitters in mammals, while microbial MAOs have been shown to be valuable biocatalysts for enantioselective synthesis of pharmaceutical compounds or precursors thereof. To extend the knowledge of how MAOs function at the molecular level and in order to provide more biocatalytic tools, we set out to identify and study a robust bacterial variant: a MAO from the thermophile Thermoanaerobacterales bacterium (MAO ). MAO is highly thermostable with melting temperatures above 73 °C and is well expressed in Escherichia coli. Substrate screening revealed that the oxidase is most efficient with n-alkylamines with n-heptylamine being the best substrate. Presteady-state kinetic analysis shows that reduced MAO rapidly reacts with molecular oxygen, confirming that it is a bona fide oxidase. The crystal structure of MAO was resolved at 1.5 Å and showed an exceptionally high similarity with the two human MAOs, MAO A and MAO B. The active site of MAO resembles mostly the architecture of human MAO A, including the cysteinyl protein-FAD linkage. Yet, the bacterial MAO lacks a C-terminal extension found in human MAOs, which explains why it is expressed and purified as a soluble protein, while the mammalian counterparts are anchored to the membrane through an α-helix. MAO also displays a slightly different active site access tunnel, which may explain the specificity toward long aliphatic amines. Being an easy-to-express, thermostable enzyme, for which a high-resolution structure was elucidated, this bacterial MAO may develop into a valuable biocatalyst for synthetic chemistry or biosensing.

PubMed: 37814408
DOI: 10.1111/febs.16973

Experimental method

X-RAY DIFFRACTION (1.5 Å)