Preparation of Free and of Specifically Protected Oligo[β-Malic Acids] for Enzymatic Degradation Studies

Krell, Christoph M.; Seebàch, Dieter

doi:10.1002/1099-0690(200004)2000:7<1207::aid-ejoc1207>3.0.co;2-2

Cited by 24 publications

(15 citation statements)

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“…21 Ester backbone chemistry is particularly attractive because it provides straightforward access to longer oligomers via stepwise synthesis from orthogonally protected monomers. [23][24][25][26][27][28][29][30] Here we describe the synthesis of the ADAD 4-mer and show that there are emergent supramolecular assembly properties that resemble those found in nucleic acids.…”

Section: Introductionmentioning

confidence: 99%

Emergent supramolecular assembly properties of a recognition-encoded oligoester

2019

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The sequences of oligomeric molecules equipped with interacting side-chains encode the threedimensional structure, the supramolecular assembly properties, and ultimately function. In an attempt to replicate the duplex forming properties of nucleic acids, an oligoester containing an alternating sequence of hydrogen bonding donor (D) and acceptor (A) residues was synthesised. Characterisation of assembly properties of the ADAD oligomer revealed a supramolecular architecture that resembles the kissing stem-loops motif found in folded RNA. NMR dilution and melting experiments in chloroform and 1,1,2,2-tetrachloroethane show that intramolecular hydrogen bonding interactions between the terminal phenol and phosphine oxide recognition sites in the ADAD 4-mer lead to 1,4-folding. This folded stemloop structure can be denatured to give the single strand by heating. At higher concentrations or lower temperatures, the stem-loop dimerises via intermolecular hydrogen bonding interactions between the two inner recognition sites, leading to a kissing stem-loops structure. The results suggest a rich supramolecular chemistry for these recognition-encoded oligoesters and lay strong foundations for the future development of new functional materials based on synthetic information molecules.

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Section: Introductionmentioning

confidence: 99%

Emergent supramolecular assembly properties of a recognition-encoded oligoester

2019

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“…A successful route to BSH ( 1 ) was finally established via 12 b (Scheme ) whose allyl esters were readily removed using catalytic [Pd(PPh 3 ) 4 ] in the presence of excess imidazole 16. Subsequent removal of the acetate protecting groups under mild Zemplén conditions provided 13 .…”

Section: Methodsmentioning

confidence: 99%

Chemical and Chemoenzymatic Syntheses of Bacillithiol: A Unique Low‐Molecular‐Weight Thiol amongst Low G + C Gram‐Positive Bacteria

et al. 2011

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“…One U of polymalatase activity is defined by the amount of enzyme that releases 1 µg of l ‐malate (potassium salt) in 1 h at standard assay conditions (37.5 µg PMLA, potassium salt, see kinetics section). The syntheses of β‐di( l ‐malic acid), β‐tetra( l ‐malic acid), β‐tetra( l ‐malic acid) β‐propylester, O‐terminal acetate of β‐tetra( l ‐malic acid), cyclic β‐tri( l ‐malic acid), and cyclic β‐tetra( l ‐malic acid) have been described [12]. l ‐Malic acid β‐methylester and d ‐malic acid β‐methylester were synthesized enzymatically as follows [13]: The l ‐ or d ‐malate α,β‐dimethylester (2.15 mmol from Merck, Germany and Fluka, Switzerland) in 10 mL of 50 m m sodium phosphate buffer (pH 8.6) was cleaved with 34.5 U of porcine liver esterase (Sigma) for 7 h at 37 °C.…”

Section: Methodsmentioning

confidence: 99%

Synthetic substrates and inhibitors of β‐poly(L‐malate)‐hydrolase (polymalatase)

Gasslmaier

Krell

Seebàch

et al. 2000

European Journal of Biochemistry

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Polymalatase from Physarum polycephalum calalysed the hydrolysis of b-poly [l-malate] and of the synthetic compounds b-di(l-malate), b-tetra(l-malate), b-tetra(l-malate) b-propylester, and l-malate b-methylester. Cyclic b-tri(l-malate), cyclic b-tetra(l-malate), and d-malate b-methylester were not cleaved, but were competitive inhibitors. The O-terminal acetate of b-tetra(l-malate) was neither a substrate nor an inhibitor. l-Malate was liberated; the K m, K i and V max values were measured. The appearance of comparable amounts of b-tri(l-malate), and b-di(l-malate) during the cleavage of b-tetra(l-malate) indicated a distributive mechanism for small substrates. The accumulation of a series of oligomers, peaking with the 11-mer and 12-mer in the absence of higher intermediates, indicated that the depolymerization of b-poly(l-malate) was processive. The results indicate that b-poly(l-malate) is anchored at its OH-terminus by the highly specific binding of the penultimate malyl residue. The malyl moieties beyond 12 residues downstream from the OH-terminus extend into a diffuse second, electrostatic binding site. The catalytic site joins the first binding site, accounting for the cleavage of the polymer into malate residues. It is proposed that the enzyme does not dissociate from b-poly(l-malate) during hydrolysis, when both sites are filled with the polymer. When only the first binding site is filled, the reaction partitions at each oligomer between hydrolysis and dissociation.Keywords: polymalatase; polymalate; depolymerase; synthetic substrates; inhibitors.The plasmodium of Physarum polycephalum and of other myxomycetes produces b-poly(l-malate) (PMLA), an unbranched polyester of l-malic acid [1,2]. The highly charged polyanion binds the replicative DNA polymerases, histones, and other nuclear proteins forming higher-order protein complexes in the nuclei of only these types of cells [3,4±6]. Plasmodia are multinucleated cells typical for myxomycetes in the vegetative branch of their life cycle [7]. Because they develop into cells of extreme sizes and yet display a high degree of synchrony in the timing of cellular events, PMLA has been proposed to function as a storage and carrier matrix in the maintenance of an adequate supply of proteins for all nuclei. In high PMLA-producer strains, the polymer is secreted into the culture medium and depolymerized to l-malate. The hydrolase (polymalatase) has been identified and characterized [8]. The catalytic activity has its optimum at pH 3.5. The large quantity of polymalatase found in the extract of the plasmodium probably refers to the zymogen, which is spontaneously activated during cell lysis [9].Protein chemistry and inhibitor studies have suggested a catalytic mechanism that is unusual for esterases [8]. Structure±function correlation studies with PMLA-derivatives have indicated that the enzyme cleaves the ester bonds while moving in a downstream direction from the OH-terminus [10]. Because of their hydrolytic instability, the employed inhibitors and substrates were...

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Preparation of Free and of Specifically Protected Oligo[β-Malic Acids] for Enzymatic Degradation Studies

Cited by 24 publications

References 49 publications

Emergent supramolecular assembly properties of a recognition-encoded oligoester

Emergent supramolecular assembly properties of a recognition-encoded oligoester

Chemical and Chemoenzymatic Syntheses of Bacillithiol: A Unique Low‐Molecular‐Weight Thiol amongst Low G + C Gram‐Positive Bacteria

Synthetic substrates and inhibitors of β‐poly(L‐malate)‐hydrolase (polymalatase)

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