Structure and stereochemistry of tetrahedral inhibitor complexes of papain by direct NMR observation

Gamcsik, Michael P.; Malthouse, J. Paul G.; Primrose, William U.; Mackenzie, Neil E.; Boyd, Alan S. F.; Russell, Richard A.; Scott, Alex

doi:10.1021/ja00358a030

Cited by 56 publications

(36 citation statements)

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“…Similar experiments with a peptide aldehyde inhibitor of papain revealed a 125 ppm upfield shift upon tetrahedral adduct formation between the active-site cysteine and the aldehyde inhibitor (62). With DDAH-1, formation of a tetrahedral adduct ( 21 ) between Cys274 and the C ξ carbon of L-IPO is expected to similarly shift the resonance of C ξ considerably upfield (> 100 ppm) from its resonance in the sp 2 hybridized free ligand (Figure 5).…”

Section: Resultsmentioning

confidence: 74%

Developing Dual and Specific Inhibitors of Dimethylarginine Dimethylaminohydrolase-1 and Nitric Oxide Synthase: Toward a Targeted Polypharmacology To Control Nitric Oxide

Wang

Monzingo²,

Shi-sheng

et al. 2009

Biochemistry

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Molecules that block nitric oxide's (NO) biosynthesis are of significant interest. For example, nitric oxide synthase (NOS) inhibitors have been suggested as anti-tumor therapeutics, as have inhibitors of dimethylarginine dimethylaminohydrolase (DDAH), an enzyme that catabolizes endogenous NOS inhibitors. Dual-targeted inhibitors hold promise as more effective reagents to block NO biosynthesis than single-targeted compounds. In this study, a small set of known NOS inhibitors are surveyed as inhibitors of recombinant human DDAH-1. From these, an alkylamidine scaffold is selected for homologation. Stepwise lengthening of one substituent converts an NOS-selective inhibitor into a dual-targeted NOS/DDAH-1 inhibitor and then into a DDAH-1 selective inhibitor, as seen in the inhibition constants of N5-(1-iminoethyl)-, N5-(1-iminopropyl)-, N5-(1-iminopentyl)- and N5-(1-iminohexyl)-l-ornithine for neuronal NOS (1.7, 3, 20, >1,900 μM, respectively) and DDAH-1 (990, 52, 7.5, 110 μM, respectively). A 1.9Å X-ray crystal structure of the N5-(1-iminopropyl)-l-ornithine : DDAH-1 complex indicates covalent bond formation between the inhibitor's amidino carbon and the active-site Cys274, and solution studies show reversible competitive inhibition, consistent with a reversible covalent mode of DDAH inhibition by alkylamidine inhibitors. These represent a versatile scaffold for the development of a targeted polypharmacological approach to control NO biosynthesis.

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Section: Resultsmentioning

confidence: 74%

Developing Dual and Specific Inhibitors of Dimethylarginine Dimethylaminohydrolase-1 and Nitric Oxide Synthase: Toward a Targeted Polypharmacology To Control Nitric Oxide

Wang

Monzingo²,

Shi-sheng

et al. 2009

Biochemistry

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“…Scott's group (Texas A&M University) reported a novel direct application of NMR spectroscopy to the study of the structure and the stereochemistry of well-designed tetrahedral inhibitor complexes (198). Scott's group (Texas A&M University) reported a novel direct application of NMR spectroscopy to the study of the structure and the stereochemistry of well-designed tetrahedral inhibitor complexes (198).…”

Section: N~mentioning

confidence: 99%

Bioorganic Chemistry

Dugas¹

1989

Springer Advanced Texts in Chemistry

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“…Such a thiohemiketal adduct would be analogous to the tetrahedral adduct thought to be formed during catalysis. Substrate-derived aldehyde inhibitors whose carbonyl group is in the same position as the carbonyl of the hydrolysed peptide bond in the corresponding substrate have been shown to be potent inhibitors of papain, forming tetrahedral thiohemiacetals with the thiol group of Cys-25 [8][9][10]. However, with substrate-derived chloromethylketone [11,12] or diazoketone [13] inhibitors of papain a stable thiohemiketal is not formed ; instead, the activesite thiol is alkylated by the methylene carbon adjacent to the inhibitor carbonyl carbon which is analogous to the carbonyl of the hydrolysed peptide bond.…”

Section: Introductionmentioning

confidence: 99%

A 13C-NMR study of the inhibition of papain by a dipeptide-glyoxal inhibitor

Lowther

Djurdjevic-Pahl

Hewage

et al. 2002

Biochemical Journal

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Z-Phe-Ala-glyoxal (where Z is benzyloxycarbonyl) has been synthesized and shown to be a competitive inhibitor of papain with a Ki = 3.30±0.25nM. 13C-NMR has been used to show that in aqueous media, Z-Phe-[2-13C]Ala-glyoxal gives signals at 207.7p.p.m. and 96.3p.p.m. showing that both the α-keto carbon and its hydrate are present. When this inhibitor is bound to papain a single signal at 209.7p.p.m. is observed due to the 13C-enriched carbon. This demonstrates that the glyoxal α-keto carbon is not hydrated when it is bound to papain and that it does not form a thiohemiketal with the thiol group of Cys-25. Z-Phe-[1-13C]Ala-glyoxal has also been synthesized and its aldehyde carbon is fully hydrated in aqueous solution giving signals at 88.7p.p.m. and 90.2p.p.m. when the α-keto carbon and its hydrate are present respectively. When this inhibitor is bound to papain a single signal at 71.04p.p.m. was observed due to the 13C-enriched carbon showing that the 13C-enriched aldehyde carbon forms a thiohemiacetal with Cys-25.

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Structure and stereochemistry of tetrahedral inhibitor complexes of papain by direct NMR observation

Cited by 56 publications

References 0 publications

Developing Dual and Specific Inhibitors of Dimethylarginine Dimethylaminohydrolase-1 and Nitric Oxide Synthase: Toward a Targeted Polypharmacology To Control Nitric Oxide

Developing Dual and Specific Inhibitors of Dimethylarginine Dimethylaminohydrolase-1 and Nitric Oxide Synthase: Toward a Targeted Polypharmacology To Control Nitric Oxide

Bioorganic Chemistry

A 13C-NMR study of the inhibition of papain by a dipeptide-glyoxal inhibitor

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