Methylthioinosine Phosphorylase from<i>Pseudomonas aeruginosa</i>. Structure and Annotation of a Novel Enzyme in Quorum Sensing

Guan, R.; Ho, M.; Almo, Steven C.; Schramm, Vern L.

doi:10.1021/bi101642d

Cited by 20 publications

(28 citation statements)

References 46 publications

(74 reference statements)

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“…Although MSMEG_0990 and Rv0535 have been annotated as probable MTAPs in M. smegmatis and M. tuberculosis, respectively, the current work describes the first characterization of a bacterial MTAP. Pseudomonas isolates were thought to possess MTAP (1); however, recent work in P. aeruginosa showed that the enzyme was actually a methylthioinosine phosphorylase instead of MTAP (15). Our preliminary characterization of M. smegmatis MTAP indicated that mycobacterial MTAP may be different from human MTAP.…”

Section: Discussionmentioning

confidence: 84%

Identification and Characterization of Two Adenosine Phosphorylase Activities in Mycobacterium smegmatis

Buckoreelall

Wilson

Parker

2011

Journal of Bacteriology

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Purine nucleoside phosphorylase (PNP) is an important enzyme in purine metabolism and cleaves purine nucleosides to their respective bases. Mycobacterial PNP is specific for 6-oxopurines and cannot account for the adenosine (Ado) cleavage activity that has been detected in M. tuberculosis and M. smegmatis cultures. In the current work, two Ado cleavage activities were identified from M. smegmatis cell extracts. The first activity was biochemically determined to be a phosphorylase that could reversibly catalyze adenosine ؉ phosphate 7 adenine ؉ alpha-D-ribose-1-phosphate. Our purification scheme led to a 30-fold purification of this activity, with the removal of more than 99.9% of total protein. While Ado was the preferred substrate, inosine and guanosine were also cleaved, with 43% and 32% of the Ado activity, respectively. Our data suggest that M. smegmatis expresses two PNPs: a previously described trimeric PNP that can cleave inosine and guanosine only and a second, novel PNP (Ado-PNP) that can cleave Ado, inosine, and guanosine. Ado-PNP had an apparent K m (K m app ) of 98 ؎ 6 M (with Ado) and a native molecular mass of 125 ؎ 7 kDa. The second Ado cleavage activity was identified as 5-methylthioadenosine phosphorylase (MTAP) based on its biochemical properties and mass spectrometry analysis. Our study marks the first report of the existence of MTAP in any bacterium. Since human cells do not readily convert Ado to Ade, an understanding of the substrate preferences of these enzymes could lead to the identification of Ado analogs that could be selectively activated to toxic products in mycobacteria.

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Section: Discussionmentioning

confidence: 84%

Identification and Characterization of Two Adenosine Phosphorylase Activities in Mycobacterium smegmatis

Buckoreelall

Wilson

Parker

2011

Journal of Bacteriology

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“…specific for MTA (15) and not SAH or Ad, the middle branch (Fig. 2, middle bracket) contains the S. griseus SAHD which was found to be specific for SAH and not MTA or Ad (2).…”

Section: Resultsmentioning

confidence: 99%

“…The P. furiosus MTAP was found to catalyze the phosphorolysis of MTA and Ad, but it could also catalyze the phosphorolysis of inosine with a k cat /K m of 9.74 ϫ 10 3 M Ϫ1 s Ϫ1 (22). Recently, a 5=-methylthioinosine phosphorylase (MTIP) from Pseudomonas aeruginosa has been identified and characterized (15). Interestingly, MTIP was found to be competitively inhibited by 5=-methylthioadenosine, the annotated substrate.…”

Section: Discussionmentioning

confidence: 99%

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Identification of a 5'-Deoxyadenosine Deaminase in Methanocaldococcus jannaschii and Its Possible Role in Recycling the Radical S-Adenosylmethionine Enzyme Reaction Product 5'-Deoxyadenosine

Miller¹,

O’Brien²,

Xu³

et al. 2013

Journal of Bacteriology

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We characterize here the MJ1541 gene product from Methanocaldococcus jannaschii, an enzyme that was annotated as a 5=-methylthioadenosine/S-adenosylhomocysteine deaminase (EC 3.5.4.31/3.5.4.28). The MJ1541 gene product catalyzes the conversion of 5=-deoxyadenosine to 5=-deoxyinosine as its major product but will also deaminate 5=-methylthioadenosine, S-adenosylhomocysteine, and adenosine to a small extent. On the basis of these findings, we are naming this new enzyme 5=-deoxyadenosine deaminase (DadD). The K m for 5=-deoxyadenosine was found to be 14.0 ؎ 1.2 M with a k cat /K m of 9.1 ؋ 10 9 M ؊1 s ؊1 . Radical S-adenosylmethionine (SAM) enzymes account for nearly 2% of the M. jannaschii genome, where the major SAM derived products is 5=-deoxyadenosine. Since 5=-dA has been demonstrated to be an inhibitor of radical SAM enzymes; a pathway for removing this product must be present. We propose here that DadD is involved in the recycling of 5=-deoxyadenosine, whereupon the 5=-deoxyribose moiety of 5=-deoxyinosine is further metabolized to deoxyhexoses used for the biosynthesis of aromatic amino acids in methanogens.

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“…22 Recently the activity of MTDIH against the newly described enzyme methylthioinosine phosphorylase (MTIP) has also been published and the potential of inhibitors of MTIP as antibiotics discussed. 23 …”

Section: Introductionmentioning

confidence: 99%

Tight binding enantiomers of pre-clinical drug candidates

Evans

Cameron

Luxenburger

et al. 2015

Bioorganic & Medicinal Chemistry

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MTDIA is a picomolar transition state analogue inhibitor of human methylthioadenosine phosphorylase and a femtomolar inhibitor of E. coli methylthioadenosine nucleosidase. MTDIA has proven to be a non-toxic, orally available pre-clinical drug candidate with remarkable anti-tumour activity against a variety of human cancers in mouse xenografts. The structurally similar compound MTDIH is a potent inhibitor of human and malarial purine nucleoside phosphorylase (PNP) as well as the newly discovered enzyme, methylthioinosine phosphorylase, isolated from Pseudomonas aeruginosa. Since the enantiomers of some pharmaceuticals have revealed surprising biological activities, the enantiomers of MTDIH and MTDIA, compounds 1 and 2 respectively, were prepared and their enzyme binding properties studied. Despite binding less tightly to their target enzymes than their enantiomers compounds 1 and 2 are nanomolar inhibitors.

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Methylthioinosine Phosphorylase fromPseudomonas aeruginosa. Structure and Annotation of a Novel Enzyme in Quorum Sensing

Cited by 20 publications

References 46 publications

Identification and Characterization of Two Adenosine Phosphorylase Activities in Mycobacterium smegmatis

Identification and Characterization of Two Adenosine Phosphorylase Activities in Mycobacterium smegmatis

Identification of a 5'-Deoxyadenosine Deaminase in Methanocaldococcus jannaschii and Its Possible Role in Recycling the Radical S-Adenosylmethionine Enzyme Reaction Product 5'-Deoxyadenosine

Tight binding enantiomers of pre-clinical drug candidates

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