Escherichia coli S-adenosylmethionine decarboxylase. Subunit structure, reductive amination, and NH2-terminal sequences.

Anton, David L.; Kutny, Rusty

doi:10.1016/s0021-9258(18)61579-0

Cited by 46 publications

(18 citation statements)

References 7 publications

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“…This could reflect the composition of the catalytically active tetramer in i o as not comprising four identically processed αβ-subunits, but rather that only three of the α-subunits have an N-terminal pyruvoyl group. However, this would be unexpected in comparison with other pyruvoyldependent enzymes such as histidine decarboxylase [27] and Sadenosylmethionine decarboxylase [28], that have been shown to have one pyruvoyl group per subunit. An alternative explanation for the apparent deficit in pyruvoyl groups, and the presence of a serine residue detected at the N-terminus of the β-subunit, is the possibility of a competing process occurring in itro that derails the correct processing of the intermediate ester implicated in the formation of the pyruvoyl group (Figure 1).…”

Section: Discussionmentioning

confidence: 92%

Escherichia coli l-aspartate-α-decarboxylase: preprotein processing and observation of reaction intermediates by electrospray mass spectrometry

Ramjee

Genschel

Abell³

et al. 1997

Biochemical Journal

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The Escherichia coli panD gene, encoding l-aspartate-alpha-decarboxylase, was cloned by PCR, and shown to complement a panD mutant defective in beta-alanine biosynthesis. Aspartate decarboxylase is a pyruvoyl-dependent enzyme, and is synthesized initially as an inactive proenzyme (the pi-protein), which is proteolytically cleaved at a specific X-Ser bond to produce a beta-subunit with XOH at its C-terminus and an alpha-subunit with a pyruvoyl group at its N-terminus, derived from the serine. The recombinant enzyme, as purified, is a tetramer, and comprises principally the unprocessed pi-subunit (of 13.8 kDa), with a small proportion of the alpha- and beta-subunits (11 kDa and 2.8 kDa respectively). Incubation of the purified enzyme at elevated temperatures for several hours results in further processing. Using fluorescein thiosemicarbazide, the completely processed enzyme was shown to contain three pyruvoyl groups per tetrameric enzyme. The presence of unchanged serine at the N-terminus of some of the alpha-subunits was confirmed by electrospray mass spectrometry (ESMS) and N-terminal amino acid sequencing. A novel HPLC assay for aspartate decarboxylase was established and used to determine the Km and kcat for l-aspartate as 151+/-16 microM and 0.57 s-1 respectively. ESMS was also used to observe substrate and product adducts trapped on the pyruvoyl group by sodium cyanoborohydride treatment.

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Section: Discussionmentioning

confidence: 92%

Escherichia coli l-aspartate-α-decarboxylase: preprotein processing and observation of reaction intermediates by electrospray mass spectrometry

Ramjee

Genschel

Abell³

et al. 1997

Biochemical Journal

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“…[methionyl-3,4-14C]AdoMet (50 mCi/mmol) was obtained from RPI. AdoMet decarboxylase was isolated from E. coli strain HT 527 by a modification of the procedure of Markham et al (1982) as previously described (Anton & Kutny, 1987).…”

Section: Methodsmentioning

confidence: 99%

“…We have recently shown that AdoMet decarboxylase from E. coli is composed of two types of subunits: a, Mr 19 000; and ß, Mr 14 000 (Anton & Kutny, 1987). These probably arise from a single polypeptide (Tabor & Tabor, 1985) by an autolytic chain cleavage mechanism similar to that described for histidine decarboxylase, resulting in the generation of the pyruvoyl group on the NH2 terminus of the « subunit (Recsei & Snell, 1985).…”

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confidence: 98%

Mechanism of substrate inactivation of Escherichia coli S-adenosylmethionine decarboxylase

Anton¹,

Kutny²

1987

Biochemistry

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S-Adenosylmethionine decarboxylase, a pyruvoyl-containing decarboxylase, is inactivated in a time-dependent process under turnover conditions. The inactivation is dependent on the presence of both substrate and Mg2+, which is also required for enzyme activity. The rate of inactivation is dependent on the concentration of substrate and appears to be saturable. Inactivation by [methionyl-3,4-14C]-adenosylmethionine results in stoichiometric labeling of the protein. In contrast, when either S-[methyl-3H]adenosylmethionine or [8-14C]adenosylmethionine is used, there is virtually no incorporation of radioactivity. Automated Edman degradation of the alpha (pyruvoyl-containing) subunit reveals that substrate inactivation results in the conversion of the pyruvoyl group to an alanyl residue. These data suggest a mechanism of inactivation which involves the transamination of the nascent product to the pyruvoyl group, followed by the elimination of methylthioadenosine and the generation of a 2-propenal equivalent which could undergo a Michael addition to the enzyme. This is the first evidence for a transamination mechanism for substrate inactivation of a pyruvoyl enzyme.

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“…1995 American Chemical Society 1), dc-AdoMet (2), AdoMac (3), and AdoMao (4). the terminal pyruvate of AdoMet-DC, it is conceivable that there are additional steps involved in the inactivation process.…”

Section: Introductionmentioning

confidence: 99%

S-(5'-Deoxy-5'-adenosyl)-1-aminoxy-4-(methylsulfonio)-2-cyclopentene (AdoMao): An Irreversible Inhibitor of S-Adenosylmethionine Decarboxylase with Potent in Vitro Antitrypanosomal Activity

Guo¹,

Wu²,

Rattendi³

et al. 1995

J. Med. Chem.

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The S-adenosylmethionine (AdoMet) analogue S-(5'-deoxy-5'-adenosyl)-1-aminoxy-4-(methylsulfonio)-2-cycl opentene (AdoMao) was synthesized in two of its four possible diastereomeric forms using a facile chemoenzymatic route. The trans-1R,4R- and trans-1S,4S-diastereomers of AdoMao, as well as the corresponding diastereomers of the unmethylated precursor molecule nor-AdoMao, were then evaluated as inhibitors of S-adenosylmethionine decarboxylase (AdoMet-DC) from both bacterial and human sources. All four of the analogues acted as time-dependent, irreversible inhibitors of AdoMet-DC from Escherichia coli, exhibiting remarkably constant Ki values ranging between 20.6 and 23.7 microM. These analogues also inhibited the human form of AdoMet-DC, although this form of the enzyme was able to discriminate between AdoMao (Ki values of 21.2 microM for the trans-1R,4R form and 19.6 microM for the trans-1S,4S form) and nor AdoMao (Ki values of 95.2 microM for the trans-1R,4R form and 30.9 microM for the trans-1S,4S form). The trans diastereomers of AdoMao and nor-AdoMao were next evaluated for their ability to inhibit trypanosomal growth in vitro against cultured Trypanosoma brucei brucei bloodforms. All four of these analogues were effective growth inhibitors, with IC50 values ranging between 0.9 and 10.1 microM. The two most effective analogues, trans-1S,4S-AdoMao (IC50 0.9 microM) and trans-1S,4S-AdoMao (IC50 3.0 microM) were also effective against two clinical isolates of the pathogenic organism Trypanosoma brucei rhodesiense, KETRI 243 and KETRI 269. The most promising analogue in all respects was trans-1S,4S-AdoMao, which was subsequently found to have minimal effects on cell growth, AdoMet-DC activity, and intracellular polyamine levels in the sensitive human promyelocytic leukemia cell line HL60. Thus, the S-adenosylmethionine analogue trans-1S,4S-AdoMao acts as an effective inhibitor of AdoMet-DC and appears to serve as a parasite-specific trypanocidal agent in vitro.

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Escherichia coli S-adenosylmethionine decarboxylase. Subunit structure, reductive amination, and NH2-terminal sequences.

Cited by 46 publications

References 7 publications

Escherichia coli l-aspartate-α-decarboxylase: preprotein processing and observation of reaction intermediates by electrospray mass spectrometry

Escherichia coli l-aspartate-α-decarboxylase: preprotein processing and observation of reaction intermediates by electrospray mass spectrometry

Mechanism of substrate inactivation of Escherichia coli S-adenosylmethionine decarboxylase

S-(5'-Deoxy-5'-adenosyl)-1-aminoxy-4-(methylsulfonio)-2-cyclopentene (AdoMao): An Irreversible Inhibitor of S-Adenosylmethionine Decarboxylase with Potent in Vitro Antitrypanosomal Activity

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