Discovery and Characterization of BlsE, a Radical S-Adenosyl-L-methionine Decarboxylase Involved in the Blasticidin S Biosynthetic Pathway

Feng, Jun; Wu, Jun; Dai, Nan; Lin, Shuangjun; Xu, H. Howard; Deng, Zixin; He, Xinyi

doi:10.1371/journal.pone.0068545

Cited by 15 publications

(16 citation statements)

References 43 publications

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“…For example, compared to the amino acid racemases of primary metabolism, which employ Lewis acid-base chemistry, the reactions catalyzed by PoyD/YydG are essentially irreversible due to the net reduction of SAM. 61,63 However, this does not seem consistent with the reactions catalyzed by NosL, AprD4 and the redox-neutral decarboxylase BlsE 64,65 among others, where the need for a thermodynamic driving force would not be expected. Furthermore, similar chemistry has also been implicated in the case of spore photoproduct lyase where SAM is indeed regenerated.…”

Section: Redox Neutral Transformationsmentioning

confidence: 83%

Following the electrons: peculiarities in the catalytic cycles of radical SAM enzymes

2018

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Radical SAM enzymes use S-adenosyl-l-methionine as an oxidant to initiate radical-mediated transformations that would otherwise not be possible with Lewis acid/base chemistry alone. These reactions are either redox neutral or oxidative leading to certain expectations regarding the role of SAM as either a reusable cofactor or the ultimate electron acceptor during each turnover. However, these expectations are frequently not realized resulting in fundamental questions regarding the redox handling and movement of electrons associated with these biological catalysts. Herein we provide a focused perspective on several of these questions and associated hypotheses with an emphasis on recently discovered radical SAM enzymes.

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Section: Redox Neutral Transformationsmentioning

confidence: 83%

Following the electrons: peculiarities in the catalytic cycles of radical SAM enzymes

2018

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“…The reaction was carried out in the presence of L-arginine, ␣-ketoglutaric acid, L-aspartate, SAM, PLP, ArgM, and ArgN at 25°C for 3 h. Reactions were derivatized with DNS-Cl and quenched by 10% ethylamine, and reactions mixtures were subjected to an Agilent semipreparative column (Zorbax ODS, 5-m particle size, 9.4 by 250 mm). The same fragments of DNS-␤mArg were combined, concentrated, and analyzed for their 1 H NMR (500-MHz, methanol-d4) and 13 S11 to S12 in the supplemental material). Further COSY NMR clearly showed that the H · H protons of the ␣-carbon and ␤-methyl groups were correlated, thus proving the configuration of the (3R)-methyl group of DNS-␤mArg (Fig.…”

Section: Resultsmentioning

confidence: 99%

Biosynthesis of the β-Methylarginine Residue of Peptidyl Nucleoside Arginomycin in Streptomyces arginensis NRRL 15941

Feng

Gao

et al. 2014

Appl Environ Microbiol

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bThe peptidyl nucleoside arginomycin is active against Gram-positive bacteria and fungi but displays much lower toxicity to mice than its analog blasticidin S. It features a rare amino acid, ␤-methylarginine, which is attached to the deoxyhexose moiety via a 4=-aminoacyl bond. We here report cloning of the complete biosynthetic gene cluster for arginomycin from Streptomyces arginensis NRRL 15941. Among the 14 putative essential open reading frames, argM, encoding an aspartate aminotransferase (AAT), and adjacent argN, encoding an S-adenosyl methionine (SAM)-dependent methyltransferase, are coupled to catalyze arginine and yield ␤-methylarginine in Escherichia coli. Purified ArgM can transfer the ␣-amino group of L-arginine to ␣-ketoglutaric acid to give glutamate and thereby converts L-arginine to 5-guanidino-2-oxopentanoic acid, which is methylated at the C-3 position by ArgN to form 5-guanidino-3-methyl-2-oxopentanoic acid. Iteratively, ArgM specifically catalyzes transamination from the donor L-aspartate to the resulting 5-guanidino-3-methyl-2-oxopentanoic acid, generating ␤-methylarginine. The complete and concise biosynthetic pathway for the rare and bioactive amino acid revealed by this study may pave the way for the production of ␤-methylarginine either by enzymatic conversion or by engineered living cells.A rginomycin (Fig. 1) is a peptidyl nucleoside antibiotic isolated from Streptomyces arginensis NRRL 15941 that shows bioactivity against Gram-positive bacteria and fungi, such as Micrococcus luteus and Penicillium oxalicum (1). Although the overall skeleton of arginomycin is highly similar to that of blasticidin S (BS) (Fig. 1), a representative peptidyl nucleoside antibiotic exhibiting strong inhibitory activity against rice blast caused by Pyricularia oryzae Cavara (2), arginomycin showed much lower toxicity to mice (1). They differ from each other only in the modification of the L-arginine-derived guanidino side chain (Fig. 1). A feeding experiment indicated that ␤-arginine in BS is derived from an intramolecular amino migration of ␣-arginine (3). BlsG, an arginine 2,3-aminomutase homologous to lysine 2,3-aminomutase (4), was assumed to govern this migration in the BS biosynthesis pathway. In contrast, ␦-N-methylation was demonstrated to be the ultrabiosynthetic step, as the conversion of demethylblasticidin S to BS was observed in a cell extract of the BS producer Streptomyces griseochromogenes supplied with radiolabeled S-adenosyl-L-methionine (SAM) (5). Likewise, ␦-N-methylation of the guanidyl group of arginomycin should also occur after attachment of the guanidino side chain to the nucleoside core moiety. In addition to this, arginomycin bears at the relatively unreactive ␤ position of arginine the ␤-methylarginine moiety for which ␤-methylation is a commitment step and is of considerable interest to this study in uncovering new enzymology. There are two possibilities for the timing of the ␤-methylation of arginine: (i) L-arginine is first converted to free ␤-methylarginine and is coupled with ...

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“…Production of BEA is time‐dependent, and its yield is about 20‐fold and 8‐fold higher than that of MBA and MB, respectively (Figure 2 D), suggesting that NosL was transformed to a non‐oxidative decarboxylase by ABPA. To data, BlsE involved in the biosynthesis of the peptidyl nucleoside antibiotic Blasticidin S is the only known radical SAM enzyme that catalyzes a non‐oxidative decarboxylation reaction 17. The sequence similarity between BlsE and NosL is barely detectable, demonstrating the remarkable catalytic versatility of radical SAM superfamily enzymes.…”

mentioning

confidence: 99%

Substrate‐Tuned Catalysis of the Radical S‐Adenosyl‐L‐Methionine Enzyme NosL Involved in Nosiheptide Biosynthesis

Ding

et al. 2015

Angew Chem Int Ed

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NosL is a radical S-adenosyl-L-methionine (SAM) enzyme that converts L-Trp to 3-methyl-2-indolic acid, a key intermediate in the biosynthesis of a thiopeptide antibiotic nosiheptide. In this work we investigated NosL catalysis by using a series of Trp analogues as the molecular probes. Using a benzofuran substrate 2-amino-3-(benzofuran-3-yl)propanoic acid (ABPA), we clearly demonstrated that the 5'-deoxyadenosyl (dAdo) radical-mediated hydrogen abstraction in NosL catalysis is not from the indole nitrogen but likely from the amino group of L-Trp. Unexpectedly, the major product of ABPA is a decarboxylated compound, indicating that NosL was transformed to a novel decarboxylase by an unnatural substrate. Furthermore, we showed that, for the first time to our knowledge, the dAdo radical-mediated hydrogen abstraction can occur from an alcohol hydroxy group. Our study demonstrates the intriguing promiscuity of NosL catalysis and highlights the potential of engineering radical SAM enzymes for novel activities.

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Discovery and Characterization of BlsE, a Radical S-Adenosyl-L-methionine Decarboxylase Involved in the Blasticidin S Biosynthetic Pathway

Cited by 15 publications

References 43 publications

Following the electrons: peculiarities in the catalytic cycles of radical SAM enzymes

Following the electrons: peculiarities in the catalytic cycles of radical SAM enzymes

Biosynthesis of the β-Methylarginine Residue of Peptidyl Nucleoside Arginomycin in Streptomyces arginensis NRRL 15941

Substrate‐Tuned Catalysis of the Radical S‐Adenosyl‐L‐Methionine Enzyme NosL Involved in Nosiheptide Biosynthesis

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