A proposed update for the classification and description of bacterial lipolytic enzymes.

Thomas C.A Hitch,Thomas Clavel

doi:10.7717/peerj.7249

Abstract

Bacterial lipolytic enzymes represent an important class of proteins: they provide their host species with access to additional resources and have multiple applications within the biotechnology sector. Since the formalisation of lipolytic enzymes into families and subfamilies, advances in molecular biology have led to the discovery of lipolytic enzymes unable to be classified via the existing system. Utilising sequence-based comparison methods, we have integrated these novel families within the classification system so that it now consists of 35 families and 11 true lipase subfamilies. Representative sequences for each family and subfamily have been defined as well as methodology for accurate comparison of novel sequences against the reference proteins, facilitating the future assignment of novel proteins. Both the code and protein sequences required for integration of additional families are available at: https://github.com/thh32/Lipase_reclassification.

Highlights

Bacterial lipolytic enzymes are involved in a diverse range of microbial functions from metabolism of fat for energy (Drouault et al, 2002) to pathogenesis (Canaan et al, 2004)
The alpha-beta hydrolase family contains both lipases (Enzyme commission (EC): 3.1.1.3) and carboxylesterases (EC: 3.1.1.1), both of which can catalyse the hydrolysis of 4-nitrophenyl-bound fatty acids (Guo et al, 2010; Rao et al, 2011)
This separates the lipases from the esterases, which may have activity against p-nitrophenyl-bound fatty acids but are unable to act upon triacylglycerol molecules (Yu et al, 2010; Masomian et al, 2016)

Summary

Introduction

Bacterial lipolytic enzymes are involved in a diverse range of microbial functions from metabolism of fat for energy (Drouault et al, 2002) to pathogenesis (Canaan et al, 2004). Lipases are defined as those which display some ability to catalyse the release of free fatty acids from long-chain triacylglycerols, such as those found in plant oil and animal fat, activity may be highest against short or medium chain fatty acids (Jaeger & Eggert, 2002;Levisson, Van der Oost & Kengen, 2007; Glogauer et al, 2011) This separates the lipases from the esterases, which may have activity against p-nitrophenyl (pNP)-bound fatty acids (a standard test for substrate specificity) but are unable to act upon triacylglycerol molecules (Yu et al, 2010; Masomian et al, 2016). The gold standard classification system of bacterial lipolytic enzymes was originally published by Arpigny & Jaeger (1999)

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