Crystal structures of a novel family IV esterase in free and substrate‐bound form

Bacterial lipolytic enzymes of family IV are homologs the mammalian hormone-sensitive lipases (HSL) and have been successfully used for various biotechnological applications. The broad substrate specificity ability enantio-, regio-, stereoselective hydrolysis remarkable features from this class. Many crystal structures available esterases lipases, but enzyme–substrate or enzyme–inhibitor complexes less frequent although important to understand molecular basis interaction rationalize biochemical enzyme characteristics. Here, we report on a novel esterase isolated metagenomic screen, which shows specificity. We solved in apo form with bound analogue at 1.35 1.81 Å resolution, respectively. This named PtEst1 hydrolyzed more than 60 out 96 structurally different ester substrates thus being promiscuous. Its is accord large active site cavity, covered by an α-helical cap domain. methyl 4-methylumbelliferyl hexylphosphonate was rapidly leading complete inactivation caused covalent binding phosphinic acid catalytic serine. Interestingly, alcohol leaving group 4-methylumbelliferone found remaining additionally, inhibitor molecule domain next entrance tunnel. unique situation allowed gaining valuable insights into role belonging IV. Database Structural data worldwide protein bank (https://www.rcsb.org) under accession codes: 6Z68 (apo-PtEst1) 6Z69 (PtEst1-inhibitor complex).