93864-65-4

Upstream product

• 21566-74-5 (L-α-amino-δ-adipyl)-L-cysteinyl-D-valine 

Downstream Products

• 85989-38-4 (2S,5R,6R)-6-((S)-5-Ethoxycarbonylamino-5-methoxycarbonyl-pentanoylamino)-3,3-dimethyl-7-oxo-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylic acid methyl ester 

Relevant academic research and scientific papers

The Interaction of Isopenicillin N Synthase with Homologated Substrate Analogues δ-(L-α-Aminoadipoyl)-L-homocysteinyl-D-Xaa Characterised by Protein Crystallography

Isopenicillin N synthase (IPNS) converts the linear tripeptide δ-(L-α-aminoadipoyl)-L-cysteinyl-D-valine (ACV) into bicyclic isopenicillin N (IPN) in the central step in the biosynthesis of penicillin and cephalosporin antibiotics. Solution-phase incubation experiments have shown that IPNS turns over analogues with a diverse range of side chains in the third (valinyl) position of the substrate, but copes less well with changes in the second (cysteinyl) residue. IPNS thus converts the homologated tripeptides δ-(L-α-aminoadipoyl)-L-homocysteinyl-D-valine (AhCV) and δ-(L-α-aminoadipoyl)-L-homocysteinyl-D-allylglycine (AhCaG) into monocyclic hydroxy-lactam products; this suggests that the additional methylene unit in these substrates induces conformational changes that preclude second ring closure after initial lactam formation. To investigate this and solution-phase results with other tripeptides δ-(L-α-aminoadipoyl)-L-homocysteinyl-D-Xaa, we have crystallised AhCV and δ-(L-α-aminoadipoyl)-L-homocysteinyl-D-S-methylcysteine (AhCmC) with IPNS and solved crystal structures for the resulting complexes. The IPNS:FeII:AhCV complex shows diffuse electron density for several regions of the substrate, revealing considerable conformational freedom within the active site. The substrate is more clearly resolved in the IPNS:FeII:AhCmC complex, by virtue of thioether coordination to iron. AhCmC occupies two distinct conformations, both distorted relative to the natural substrate ACV, in order to accommodate the extra methylene group in the second residue. Attempts to turn these substrates over within crystalline IPNS using hyperbaric oxygenation give rise to product mixtures. Loose fit: IPNS catalyses the central step in penicillin biosynthesis. Substrate analogues containing L-homocysteine in place of the natural substrate's L-cysteine residue are not converted into bicyclic products. Crystal structures for IPNS complexes with two such analogues reveal that the additional CH2 unit affords considerable conformational freedom when these analogues bind to IPNS. Copyright

The crystal structure of isopenicillin N synthase with δ-(l-α- aminoadipoyl)-l-cysteinyl-d-methionine reveals thioether coordination to iron

Isopenicillin N synthase (IPNS) catalyses cyclization of δ-(l-α-aminoadipoyl)-l-cysteinyl-d-valine (ACV) to isopenicillin N (IPN), the central step in penicillin biosynthesis. Previous studies have shown that IPNS turns over a wide range of substrate analogues in which the valine residue of its natural substrate is replaced with other amino acids. IPNS accepts and oxidizes numerous substrates that bear hydrocarbon sidechains in this position, however the enzyme is less tolerant of analogues presenting polar functionality in place of the valinyl isopropyl group. We report a new ACV analogue δ-(l-α-aminoadipoyl)-l-cysteinyl-d-methionine (ACM), which incorporates a thioether in place of the valinyl sidechain. ACM has been synthesized using solution phase methods and crystallized with IPNS. A crystal structure has been elucidated for the IPNS:Fe(II):ACM complex at 1.40 resolution. This structure reveals that ACM binds in the IPNS active site such that the sulfur atom of the methionine thioether binds to iron in the oxygen binding site at a distance of 2.57 . The sulfur of the cysteinyl thiolate sits 2.36 from the metal.

Peculiar stability of amino acids and peptides from a radical perspective

(Chemical Equation Presented) Photochemical reactions of free and N-acetyl α-amino acids with chlorine and deuterium labeled hydrogen peroxide have been used to determine both the relative rates of reaction of molecules of these classes and the relative reactivity of their different types of hydrogen toward abstraction by chlorine and oxygen centered radicals. The relative rates of reaction of these species range over more than 3 orders of magnitude; however, where data are available from more than one amino acid for a particular type of group at a specific position on the side chain, the values are remarkably similar. The predictive utility of these results has been demonstrated for the regioselective chlorination of tripeptides. More generally this analysis shows that the backbone and adjacent side chain positions of amino acids and peptides are peculiarly resistant to hydrogen atom transfer, and a similar pattern of reactivity has been noted from earlier studies of reactions of modified substrates catalyzed by isopenicillin-N-synthetase. Such resistance stands out in contrast to the common occurrence of free radical reactions of α-amino acids, peptides, and proteins and their importance in biology. Nevertheless, it provides a reason for the ability of amino acids and their derivatives to avoid degradation in Nature where they are constantly exposed to radicals, and it accounts, at least in part, for the anomalous ability of enzymes to catalyze free radical reactions without being broken down by the radical intermediates.

Penicillin Biosynthesis: Direct Biosynthetic Formation of Penicillin V and Penicillin G

The enzyme isopenicillin N synthetase is able to convert directly the dipeptides, phenoxyacetylcysteinylvaline and phenylacetylcysteinylvaline into penicillin V and G respectively; these are however very slow compared with substrates of the α-aminoadipoyl or adipoylcysteinylvaline type.

CONVERSION OF 17O/18O LABELLED δ-(L-α-AMINOADIPYL)-L-CYSTEINYL-D-VALINE TO 17O/18O LABELLED ISOPENICILLIN IN A CELL-FREE EXTRACT OF CEPHALOSPORIUM ACREMONIUM. A STUDY BY 17O-NMR SPECTROSCOPY AND MASS SPECTROMETRY.

δ-(L-α-Amino17O/18O>-adipyl)-L-cystinyl-D-valine was converted into isopenicillin N in cell-free extracts of Cephalosporium acremonium with no loss of 17O/18O label as shown by 17O NMR spectroscopy and mass spectrometry.Incubation of unlabelled tripeptide in a cell-free system containing 17O/18O enriched water produced isopenicillin N with no incorporation of 17O/18O.

Conversion of 17O/18O-Labelled &δ-(L-&α-Aminoadipyl)-L-cysteinyl-D-valine into 17O/18O-Labelled Isopenicillin N in a Cell-free Extract of C. acremonium

δ-(L-α-Amino17O/18O>-adipyl)-L-cysteinyl-D-valine was converted into isopenicillin N in cell-free extracts of Cephalosporium acremonium with no loss of 17O/18O label as shown by 17O n.m.r. spectroscopy and mass spectrometry; incubation of unlabelled tripeptide in a cell-free system containing 17O/18O-enriched water produced isopenicillin N with no incorporation of 17O/18O.

Direct 1H N.M.R. Observation of the Cell-free Conversion of δ-(L-α-Aminoadipyl)-L-cysteinyl-D-valine and δ-(L-α-Aminoadipyl)-L-cysteinyl-D-(-)-isoleucine into Penicillins

The cell-free conversion of δ-(L-aminoadipyl)-L-cysteinyl-D-(-)-isoleucine (1b) into a penicillin (2b) was observed directly by 1H n.m.r. spectroscopy and the thiazolidine ring formation was shown to occur with retention of stereochemistry at C-3 of the isoleucinyl residue by 1H nuclear Overhauser enhancement studies of the product penicillin in the deproteinated incubation mixture.

Direct N.m.r. Observation of Cell-free Conversion of (L-α-Amino-δ-adipyl)-L-cysteinyl-D-valine into Isopenicillin N

Carbon-13 n.m.r. spectroscopy has been used to observe the efficient conversion of (L-α-amino-δ-adipyl)-L-cysteinyl-D-valine into isopenicillin N in cell-free extracts of Cephalosporium acremonium.