A novel thermophilic and halophilic esterase from Janibacter sp. R02, the first member of a new lipase family (Family XVII)

Bacillus sp. JR3 esterase LipJ: A new mesophilic enzyme showing traces of a thermophilic past

“…JR3, and suggest that the cloned enzyme LipJ is not the thermophilic enzyme we intended to clone. On the contrary, the catalytic behaviour of LipJ points to a mesophilic esterase that could even be intracellular, based on the fact that most secreted Bacillus -related lipases are alkaliphilic [12,54,55], while LipJ only shows activity at neutral pH, as happens for most intracellular esterases [56–58]. …”

“…Moreover, putative Ca 2+ and Zn 2+ -binding cavities [45,46,65,76] could also be predicted for LipJ after superposition of the three enzyme structures (Fig 7B), suggesting that LipJ could either be activated or dependent on such ions for activity. In fact, most described thermophilic and thermoalkaliphilic lipases bear either a Ca 2+ or Zn 2+ -binding site, or both (seldom other ions; [12]), acting through a specific net of salt bridges [46,77] that have been shown to be essential for thermophilic activity and thermoresistance [21,65]. …”

“…Their active site is constituted by a catalytic triad containing a serine as the catalytic residue, an aspartic or glutamic acid, and a histidine, usually being the nucleophile serine embedded in the GX S XG consensus pentapeptide [2,9]. Bacterial lipolytic enzymes were initially classified into eight families [10], with successive revisions up to more than 16 families described nowadays [9,11,12]. These classifications are based on amino acid sequence homology and the presence of conserved motifs, although more recently, certain structural features and phylogenetic analysis have come to complement this classification [9–12].…”

“…Bacterial lipolytic enzymes were initially classified into eight families [10], with successive revisions up to more than 16 families described nowadays [9,11,12]. These classifications are based on amino acid sequence homology and the presence of conserved motifs, although more recently, certain structural features and phylogenetic analysis have come to complement this classification [9–12]. …”

Peer Review #3 of "A proposed update for the classification and description of bacterial lipolytic enzymes (v0.1)"

“…Jaeger and Eggert (2002) redefined these families by splitting family I.5 into two new families, family I.5 and family I.6, and moving the previous members of family I.6 into family I.7 (Jaeger & Eggert, 2002). In the 20 years since this bacterial lipolytic enzyme classification system was published, more than twice as many 'novel' families have been proposed (Handrick et al, 2001;Ewis, Abdelal & Lu, 2004;Lee et al, 2010Lee et al, , 2006Levisson, van der Oost & Kengen, 2007;Bender et al, 2009;Kim et al, 2009;Hu et al, 2010;Rao et al, 2011;Jeon et al, 2011;Bassegoda, Pastor & Diaz, 2012;Charbonneau & Beauregard, 2013;Zarafeta et al, 2016;Castilla et al, 2017;Parapouli et al, 2018). A recent update to this system expanded the system to include some (11 of 30) of the recently published novel lipases within 19 families and 8 true lipase sub-families, however many lipolytic proteins remain unclassified (Kovacic et al, 2019).…”