26892-00-2Relevant articles and documents
S-Adenosyl-l-ethionine is a Catalytically Competent Analog of S-Adenosyl-l-methionine (SAM) in the Radical SAM Enzyme HydG
Impano, Stella,Yang, Hao,Shepard, Eric M.,Swimley, Ryan,Pagnier, Adrien,Broderick, William E.,Hoffman, Brian M.,Broderick, Joan B.
, p. 4666 - 4672 (2021)
Radical S-adenosyl-l-methionine (SAM) enzymes initiate biological radical reactions with the 5′-deoxyadenosyl radical (5′-dAdo.). A [4Fe-4S]+ cluster reductively cleaves SAM to form the Ω organometallic intermediate in which the 5′-deoxyadenosyl moiety is directly bound to the unique iron of the [4Fe-4S] cluster, with subsequent liberation of 5′-dAdo.. We present synthesis of the SAM analog S-adenosyl-l-ethionine (SAE) and show SAE is a mechanistically equivalent SAM-alternative for HydG, both supporting enzymatic turnover of substrate tyrosine and forming the organometallic intermediate Ω. Photolysis of SAE-bound HydG forms an ethyl radical trapped in the active site. The ethyl radical withstands prolonged storage at 77 K and its EPR signal is only partially lost upon annealing at 100 K, making it significantly less reactive than the methyl radical formed by SAM photolysis. Upon annealing above 77 K, the ethyl radical adds to the [4Fe-4S]2+ cluster, generating an ethyl-[4Fe-4S]3+ organometallic species termed ΩE.
Rationally engineered variants of S-adenosylmethionine (SAM) synthase: Reduced product inhibition and synthesis of artificial cofactor homologues
Dippe,Brandt,Rost,Porzel,Schmidt,Wessjohann
, p. 3637 - 3640 (2015/03/30)
S-Adenosylmethionine (SAM) synthase was engineered for biocatalytic production of SAM and long-chain analogues by rational re-design. Substitution of two conserved isoleucine residues extended the substrate spectrum of the enzyme to artificial S-alkylhomocysteines. The variants proved to be beneficial in preparative synthesis of SAM (and analogues) due to a much reduced product inhibition. This journal is
Chemoenzymatic synthesis and in situ application of S-adenosyl-l-methionine analogs
Thomsen, Marie,Vogensen, Stine B.,Buchardt, Jens,Burkart, Michael D.,Clausen, Rasmus P.
supporting information, p. 7606 - 7610 (2013/11/06)
Analogs of S-adenosyl-l-methionine (SAM) are increasingly applied to the methyltransferase (MT) catalysed modification of biomolecules including proteins, nucleic acids, and small molecules. However, SAM and its analogs suffer from an inherent instability, and their chemical synthesis is challenged by low yields and difficulties in stereoisomer isolation and inhibition. Here we report the chemoenzymatic synthesis of a series of SAM analogs using wild-type (wt) and point mutants of two recently identified halogenases, SalL and FDAS. Molecular modelling studies are used to guide the rational design of mutants, and the enzymatic conversion of l-Met and other analogs into SAM analogs is demonstrated. We also apply this in situ enzymatic synthesis to the modification of a small peptide substrate by protein arginine methyltransferase 1 (PRMT1). This technique offers an attractive alternative to chemical synthesis and can be applied in situ to overcome stability and activity issues.