JBIR-155, a Specific Class D β-Lactamase Inhibitor of Microbial Origin.

We discovered JBIR-155 as a novel specific class D β-lactamase inhibitor from Streptomyces polymachus SoB100815Hv02. JBIR-155 consists of a 6-oxabicyclo[3.2.0]heptan-7-one skeleton and a long unsaturated alkyl chain moiety of which absolute configuration was determined by spectroscopic data, modified Mosher's method, and analyses of the relative configuration of chemically modified derivative. JBIR-155 specifically exhibited inhibitory activity against the class D β-lactamase, with an IC50 value of 0.36 μM.