Investigation of amino acids related to Staphylococcus saprophyticus AG1 EstAG1 carboxylesterase catalytic function revealed a new family of bacterial lipolytic enzymes

Most of the lipolytic enzymes (carboxylesterases, EC 3.1.1.1 and triacylglycerol acylhydrolases, EC 3.1.1.3) originate from bacteria and form a large group of functionally important enzymes that are also well known for their use in multiple biotechnology sectors. Rapid and increasing amount of bacterial lipolytic enzymes being discovered and characterized led to a necessity to classify them. More than twenty years ago bacterial lipolytic enzymes were originally classified into eight families and six true lipase sub-families based on the differences in their amino acid sequences and biochemical properties. Later, this classification was comprehensively updated to 19 families with eight subfamilies, and more recently, employing deeper comparative analysis methods, classification expanded to 35 families and 11 subfamilies. Bacterial lipolytic enzymes that cannot be classified into currently existing families are still being discovered. This work provides site-directed mutagenesis and differential scanning fluorimetry based investigation of catalytic function-related amino acids of previously discovered and characterized EstAG1 carboxylesterase from Staphylococcus saprophyticus AG1. Experimental results obtained in this work revealed that EstAG1 carboxylesterase can be placed into a new family of bacterial lipolytic enzymes.

Automated summary

Most lipolytic enzymes originate from bacteria and have functional importance in various biotechnology sectors. They were initially classified into eight families and six lipase subfamilies based on amino acid sequences and biochemical properties. Later, this classification was expanded to 19 families and eight subfamilies, and more recently to 35 families and 11 subfamilies. This study investigated the catalytic function-related amino acids of the EstAG1 carboxylesterase from Staphylococcus saprophyticus AG1, and revealed that it belongs to a new family of bacterial lipolytic enzymes.