4G5X

Crystal structures of N-acyl homoserine lactonase AidH

Summary for 4G5X

• Entry DOI: 10.2210/pdb4g5x/pdb
• Related: 4G8B 4G8C 4G8D 4G9E 4G9G
• Descriptor: Alpha/beta hydrolase fold protein (2 entities in total)
• Functional Keywords: alpha/beta-hydrolase fold, core domain, eight-stranded sheet, lactonase, hydrolase
• Biological source: Ochrobactrum
• Total number of polymer chains: 2
• Total formula weight: 61306.73

Authors

Liang, D.C.,Yan, X.X.,Gao, A. (deposition date: 2012-07-18, release date: 2013-01-16, Last modification date: 2024-03-20)

Primary citation

Gao, A.,Mei, G.Y.,Liu, S.,Wang, P.,Tang, Q.,Liu, Y.P.,Wen, H.,An, X.M.,Zhang, L.Q.,Yan, X.X.,Liang, D.C.
High-resolution structures of AidH complexes provide insights into a novel catalytic mechanism for N-acyl homoserine lactonase
Acta Crystallogr.,Sect.D, 69:82-91, 2013

PubMed 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.

PubMed: 23275166
DOI: 10.1107/S0907444912042369

Experimental method

X-RAY DIFFRACTION (1.29 Å)