Biocatalytic Reversal of Advanced Glycation End Product Modification

Abstract

Advanced glycation end products (AGEs) are a heterogeneous group of molecules that emerge from the condensation of sugars and proteins through the Maillard reaction. Despite a significant number of studies showing strong associations between AGEs and the pathologies of aging‐related illnesses, it has been a challenge to establish AGEs as causal agents primarily due to the lack of tools in reversing AGE modifications at the molecular level. Herein, we show that MnmC, an enzyme involved in a bacterial tRNA‐modification pathway, is capable of reversing the AGEs carboxyethyl‐lysine (CEL) and carboxymethyl‐lysine (CML) back to their native lysine structure. Combining structural homology analysis, site‐directed mutagenesis, and protein domain dissection studies, we generated a variant of MnmC with improved catalytic properties against CEL in its free amino acid form. We show that this enzyme variant is also active on a CEL‐modified peptidomimetic and an AGE‐containing peptide that has been established as an authentic ligand of the receptor for AGEs (RAGE). Our data demonstrate that MnmC variants are promising lead catalysts toward the development of AGE‐reversal tools and a better understanding of AGE biology.

Engineering of Therapeutic and Detoxifying Enzymes

“…Rational and structure-guided design has also enabled the generation of enzymes for reversing cellular damage adducts, such as advanced glycation end products (AGEs). [19] AGEs are the final products of glycation, the non-enzymatic reaction between nucleophilic groups in biomolecules and reducing sugars or their metabolites. [20] A series of studies link AGEs with age-related conditions and malignant ageing.…”

Advanced Glycation End Products: New Clinical and Molecular Perspectives

“…Thoroughly, their precise mechanisms of action rely on their reactions to carbonyl groups located in the crosslinks between AGEs, subsequently promoting the spontaneous cleavage of carbon–carbon bonds at physiologic pH [ 175 ]. Likewise, an experimental study demonstrated the efficacy of MnmC, an enzyme involved in bacterial tRNA modification, capable of performing a catalytic reversion of the AGEs carboxyethyl-lysine (CEL) and carboxymethyl-lysine (CML) to lysine’s native structure [ 176 ]. The application of these drugs, mainly alagebrium, in diverse animal models has proven to be helpful in arterial stiffness reduction, blood vessel fibrosis [ 173 , 177 ], the development of atherosclerosis [ 178 ], cardiovascular disease [ 179 ], hypertension [ 180 ], and kidney injury [ 181 ].…”

Non-enzymatic covalent modifications: a new link between metabolism and epigenetics

“…Moreover, DJ-1 is also capable of converting free MGO into L/D-lactate through intermolecular hydrolysis of DJ-1 arginine and lysine residues that have reacted with the free MGO and formed early glycation intermediates (Toyoda et al, 2014;Zheng et al, 2019). Intriguingly, MnmC, which is involved in the bacterial tRNA-modification pathway and is FAD-dependent, was recently reported to be capable of reversing the AGEs, carboxyethyl-lysine (CEL) and carboxymethyl-lysine (CML), releasing an unmodified lysine structure (Kim et al, 2019). The engineered variant of MnmC has improved catalytic properties against CEL (Fig.…”

“…The engineered variant of MnmC has improved catalytic properties against CEL (Fig. 4E), thus providing insights into future protein-based therapies for AGE-induced protein damage (Kim et al, 2019).…”