Facile Chemoenzymatic Strategies for the Synthesis and Utilization of S‐Adenosyl‐L‐Methionine Analogues

Abstract

A chemoenzymatic platform for the synthesis of Sadenosyl-l-methionine (SAM) analogues compatible with downstream SAM-utilizing enzymes is reported. Forty-four non-native S/Se-alkylated Met analogues were synthesized and applied to probing the substrate specificity of five diverse methionine adenosyltransferases (MATs). Human MAT II was among the most permissive of the MATs analyzed and enabled the chemoenzymatic synthesis of 29 non-native SAM analogues. As a proof of concept for the feasibility of natural product "alkylrandomization", a small set of differentiallyalkylated indolocarbazole analogues was generated by using a coupled hMAT2-RebM system (RebM is the sugar C4'-Omethyltransferase that is involved in rebeccamycin biosynthesis). The ability to couple SAM synthesis and utilization in a single vessel circumvents issues associated with the rapid decomposition of SAM analogues and thereby opens the door for the further interrogation of a wide range of SAM utilizing enzymes.

Understanding molecular recognition of promiscuity of thermophilic methionine adenosyltransferase sMAT from Sulfolobus solfataricus

“…The ethionine turns over with sMAT and hMAT2A is near 100% whereas eMAT is just 10% [15]. A ligand-based alignment (Fig.…”

“…Also, branched analogs highlighted in Fig. 1B turnover significantly better with sMAT, comparing with eMAT, hMAT2A and mjMAT [15]. Interestingly, mjMAT is a thermophilic archaeal MAT that has all active site residues conserved with sMAT.…”

“…In addition, the slightly expanded substrate scope of sMAT over other MATs studied to date highlight sMAT as a useful tool for the production of AdoMet analogs. In conjunction with the recent demonstration of coupled MAT-methyltransferase systems for differential alkylation [15], this chemoenzymatic strategy circumvents a major liability in the use of synthetic AdoMet analogs – namely, the dramatic instability of the AdoMet analogs. Thus, the structural insights regarding sMAT provided herein offer another blueprint from which to pursue future engineering to further broaden the catalyst promiscuity toward AdoMet analog production.…”

“…4). Bars colored green (referring to branched L-alkyl-substituted analogs) denote analogs for which only trace turnover was observed with MATs studied to date [15]. As controls, no product formation was observed in the absence of sMAT, S / Se -Met analogs or ATP.…”

Probing Chromatin-modifying Enzymes with Chemical Tools

“…45 In one approach, a chemoenzymatic platform for making S-or Sealkylated analogues of SAM using different MAT enzymes has been described. 46 Another study employed bacterial halogenases SalL and FDAS for the same purpose. (Figure 3a).…”