Crystal structure of VmoLac, a tentative quorum quenching lactonase from the extremophilic crenarchaeon Vulcanisaeta moutnovskia

Julien Hiblot (1) , Janek Bzdrenga (1) , Charlotte Champion (1) , Eric Chabriere (1) , Mikael Elias (2)

1 URMITE - Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes
2 Department of Biochemistry

A new representative of the Phosphotriesterase-Like Lactonases (PLLs) family from the hyperthermophilic crenarchaeon Vulcanisaeta moutnovskia has been characterized and crystallized. VmoLac is a native, proficient lactonase with promiscuous, low phosphotriesterase activity. VmoLac therefore represents an interesting candidate for engineering studies, with the aim of developing an efficient bacterial quorum-quenching agent. Here, we provide an extensive biochemical and kinetic characterization of VmoLac and describe the X-ray structures of the enzyme bound to a fatty acid and to its cognate substrate 3-oxo-C10 AHL (Acyl-Homoserine Lactone). The structures highlight possible structural determinants that may be involved in its extreme thermal stability (Tm = 128 degrees C). Moreover, the structure reveals that the substrate binding mode of VmoLac significantly differs from those of its close homologues, possibly explaining the substrate specificity of the enzyme. Finally, we describe the specific interactions between the enzyme and its substrate, and discuss the possible lactone hydrolysis mechanism of VmoLac.

Mots clés: RECENTLY DIVERGED PHOSPHOTRIESTERASE; ARCHAEON SULFOLOBUS-SOLFATARICUS; RAY DIFFRACTION ANALYSIS; AMIDOHYDROLASE SUPERFAMILY; THERMOSTABLE PHOSPHOTRIESTERASE; BACTERIAL PHOSPHOTRIESTERASE; DEINOCOCCUS-RADIODURANS; BACILLUS-THURINGIENSIS; DIRECTED EVOLUTION; SEQUENCE ALIGNMENT

Domaines: Médecine humaine et pathologie

Julien Hiblot, Janek Bzdrenga, Charlotte Champion, Eric Chabriere, Mikael Elias. Crystal structure of VmoLac, a tentative quorum quenching lactonase from the extremophilic crenarchaeon Vulcanisaeta moutnovskia. Scientific Reports, 2015, 5 (8372), ⟨10.1038/srep08372⟩. ⟨hal-01219984⟩