3dhc

Publication Abstract from PubMed

Enzymes capable of hydrolyzing N-acyl- l-homoserine lactones (AHLs) used in some bacterial quorum-sensing pathways are of considerable interest for their ability to block undesirable phenotypes. Most known AHL hydrolases that catalyze ring opening (AHL lactonases) are members of the metallo-beta-lactamase enzyme superfamily and rely on a dinuclear zinc site for catalysis and stability. Here we report the three-dimensional structures of three product complexes formed with the AHL lactonase from Bacillus thuringiensis. Structures of the lactonase bound with two different concentrations of the ring-opened product of N-hexanoyl- l-homoserine lactone are determined at 0.95 and 1.4 A resolution and exhibit different product configurations. A structure of the ring-opened product of the non-natural N-hexanoyl- l-homocysteine thiolactone at 1.3 A resolution is also determined. On the basis of these product-bound structures, a substrate-binding model is presented that differs from previous proposals. Additionally, the proximity of the product to active-site residues and observed changes in protein conformation and metal coordination provide insight into the catalytic mechanism of this quorum-quenching metalloenzyme.

Mechanism of the quorum-quenching lactonase (AiiA) from Bacillus thuringiensis. 1. Product-bound structures.,Liu D, Momb J, Thomas PW, Moulin A, Petsko GA, Fast W, Ringe D Biochemistry. 2008 Jul 22;47(29):7706-14. PMID:18627129^[2]

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