6TWL

Apo structure of the Ectoine utilization protein EutE (DoeB) from Ruegeria pomeroyi

Summary for 6TWL

• Entry DOI: 10.2210/pdb6twl/pdb
• Descriptor: N-acetyl-L-2,4-diaminobutyric acid deacetylase (2 entities in total)
• Functional Keywords: pita bread, ectoine degradation, hydrolase
• Biological source: Ruegeria pomeroyi (strain ATCC 700808 / DSM 15171 / DSS-3)
• Total number of polymer chains: 1
• Total formula weight: 35146.95

Authors

Mais, C.-N.,Altegoer, F.,Bange, G. (deposition date: 2020-01-13, release date: 2020-05-20, Last modification date: 2024-01-24)

Primary citation

Mais, C.N.,Hermann, L.,Altegoer, F.,Seubert, A.,Richter, A.A.,Wernersbach, I.,Czech, L.,Bremer, E.,Bange, G.
Degradation of the microbial stress protectants and chemical chaperones ectoine and hydroxyectoine by a bacterial hydrolase-deacetylase complex.
J.Biol.Chem., 295:9087-9104, 2020

PubMed Abstract: When faced with increased osmolarity in the environment, many bacterial cells accumulate the compatible solute ectoine and its derivative 5-hydroxyectoine. Both compounds are not only potent osmostress protectants, but also serve as effective chemical chaperones stabilizing protein functionality. Ectoines are energy-rich nitrogen and carbon sources that have an ecological impact that shapes microbial communities. Although the biochemistry of ectoine and 5-hydroxyectoine biosynthesis is well understood, our understanding of their catabolism is only rudimentary. Here, we combined biochemical and structural approaches to unravel the core of ectoine and 5-hydroxy-ectoine catabolisms. We show that a conserved enzyme bimodule consisting of the EutD ectoine/5-hydroxyectoine hydrolase and the EutE deacetylase degrades both ectoines. We determined the high-resolution crystal structures of both enzymes, derived from the salt-tolerant bacteria and These structures, either in their apo-forms or in forms capturing substrates or intermediates, provided detailed insights into the catalytic cores of the EutD and EutE enzymes. The combined biochemical and structural results indicate that the EutD homodimer opens the pyrimidine ring of ectoine through an unusual covalent intermediate, -α-2 acetyl-l-2,4-diaminobutyrate (α-ADABA). We found that α-ADABA is then deacetylated by the zinc-dependent EutE monomer into diaminobutyric acid (DABA), which is further catabolized to l-aspartate. We observed that the EutD-EutE bimodule synthesizes exclusively the α-, but not the γ-isomers of ADABA or hydroxy-ADABA. Of note, α-ADABA is known to induce the MocR/GabR-type repressor EnuR, which controls the expression of many ectoine catabolic genes clusters. We conclude that hydroxy-α-ADABA might serve a similar function.

PubMed: 32404365
DOI: 10.1074/jbc.RA120.012722

Experimental method

X-RAY DIFFRACTION (2 Å)