Hedge_2012_Biochim.Biophys.Acta_1824_1024

Reference

Title : The structural basis for the narrow substrate specificity of an acetyl esterase from Thermotoga maritima - Hedge_2012_Biochim.Biophys.Acta_1824_1024
Author(s) : Hedge MK , Gehring AM , Adkins CT , Weston LA , Lavis LD , Johnson RJ
Ref : Biochimica & Biophysica Acta , 1824 :1024 , 2012
Abstract :

Acetyl esterases from carbohydrate esterase family 7 exhibit unusual substrate specificity. These proteins catalyze the cleavage of disparate acetate esters with high efficiency, but are unreactive to larger acyl groups. The structural basis for this distinct selectivity profile is unknown. Here, we investigate a thermostable acetyl esterase (TM0077) from Thermotoga maritima using evolutionary relationships, structural information, fluorescent kinetic measurements, and site directed mutagenesis. We measured the kinetic and structural determinants for this specificity using a diverse series of small molecule enzyme substrates, including novel fluorogenic esters. These experiments identified two hydrophobic plasticity residues (Pro228, and Ile276) surrounding the nucleophilic serine that impart this specificity of TM0077 for small, straight-chain esters. Substitution of these residues with alanine imparts broader specificity to TM0077 for the hydrolysis of longer and bulkier esters. Our results suggest the specificity of acetyl esterases have been finely tuned by evolution to catalyze the removal of acetate groups from diverse substrates, but can be modified by focused amino acid substitutions to yield enzymes capable of cleaving larger ester functionalities.

PubMedSearch : Hedge_2012_Biochim.Biophys.Acta_1824_1024
PubMedID: 22659119
Gene_locus related to this paper: thema-TM0077

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Citations formats

Hedge MK, Gehring AM, Adkins CT, Weston LA, Lavis LD, Johnson RJ (2012)
The structural basis for the narrow substrate specificity of an acetyl esterase from Thermotoga maritima
Biochimica & Biophysica Acta 1824 :1024

Hedge MK, Gehring AM, Adkins CT, Weston LA, Lavis LD, Johnson RJ (2012)
Biochimica & Biophysica Acta 1824 :1024