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Publication Abstract from PubMed

Previously, we reported the isolation of a quorum quenching protein (QQ), designated GqqA, from Komagataeibacter europaeus CECT 8546 that is highly homologous to prephenate dehydratases (PDT) (Valera et al. in Microb Cell Fact 15, 88. https://doi.org/10.1186/s12934-016-0482-y , 2016). GqqA strongly interfered with N-acyl-homoserine lactone (AHL) quorum sensing signals from Gram-negative bacteria and affected biofilm formation in its native host strain Komagataeibacter europaeus. Here we present and discuss data identifying GqqA as a novel acylase. ESI-MS-MS data showed unambiguously that GqqA hydrolyzes the amide bond of the acyl side-chain of AHL molecules, but not the lactone ring. Consistent with this observation the protein sequence does not carry a conserved Zn(2+) binding motif, known to be essential for metal-dependent lactonases, but in fact harboring the typical periplasmatic binding protein domain (PBP domain), acting as catalytic domain. We report structural details for the native structure at 2.5 A resolution and for a truncated GqqA structure at 1.7 A. The structures obtained highlight that GqqA acts as a dimer and complementary docking studies indicate that the lactone ring of the substrate binds within a cleft of the PBP domain and interacts with polar residues Y16, S17 and T174. The biochemical and phylogenetic analyses imply that GqqA represents the first member of a novel type of QQ family enzymes.

The Komagataeibacter europaeus GqqA is the prototype of a novel bifunctional N-Acyl-homoserine lactone acylase with prephenate dehydratase activity.,Werner N, Petersen K, Vollstedt C, Garcia PP, Chow J, Ferrer M, Fernandez-Lopez L, Falke S, Perbandt M, Hinrichs W, Betzel C, Streit WR Sci Rep. 2021 Jun 10;11(1):12255. doi: 10.1038/s41598-021-91536-1. PMID:34112823^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.