Structure Report for: 4G9E

Liang, D.C., Yan, X.X., Gao, A.

Title: High-resolution structures of AidH complexes provide insights into a novel catalytic mechanism for N-acyl homoserine lactonase
Gao A, Mei GY, Liu S, Wang P, Tang Q, Liu YP, Wen H, An XM, Zhang LQ and Liang DC <1 more author(s)> Gao A, Mei GY, Liu S, Wang P, Tang Q, Liu YP, Wen H, An XM, Zhang LQ, Yan XX, Liang DC (- 1)
Ref: Acta Crystallographica D Biol Crystallogr, 69:82, 2013 : PubMed
Abstract


ESTHER: Gao_2013_Acta.Crystallogr.D.Biol.Crystallogr_69_82
PubMedSearch: Gao 2013 Acta.Crystallogr.D.Biol.Crystallogr 69 82
PubMedID: 23275166
Gene_locus related to this paper: 9rhiz-d2j2t6
Inhibitor(s) related to this paper: N-Hexanoyl-L-Homoserine, N-butanoyl-L-homoserine

Abstract

Many pathogenic bacteria that infect humans, animals and plants rely on a quorum-sensing (QS) system to produce virulence factors. N-Acyl homoserine lactones (AHLs) are the best-characterized cell-cell communication signals in QS. The concentration of AHL plays a key role in regulating the virulence-gene expression and essential biological functions of pathogenic bacteria. N-Acyl homoserine lactonases (AHL-lactonases) have important functions in decreasing pathogenicity by degrading AHLs. Here, structures of the AHL-lactonase from Ochrobactrum sp. (AidH) in complex with N-hexanoyl homoserine lactone, N-hexanoyl homoserine and N-butanoyl homoserine are reported. The high-resolution structures together with biochemical analyses reveal convincing details of AHL degradation. No metal ion is bound in the active site, which is different from other AHL-lactonases, which have a dual Lewis acid catalysis mechanism. AidH contains a substrate-binding tunnel between the core domain and the cap domain. The conformation of the tunnel entrance varies with the AHL acyl-chain length, which contributes to the binding promiscuity of AHL molecules in the active site. It also supports the biochemical result that AidH is a broad catalytic spectrum AHL-lactonase. Taken together, the present results reveal the catalytic mechanism of the metal-independent AHL-lactonase, which is a typical acid-base covalent catalysis.