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Studies on the biosynthetic pathways of clavulanic acid and cephamycin C in Streptomyces clavuligerus

Mackenzie, Alasdair (2007). Studies on the biosynthetic pathways of clavulanic acid and cephamycin C in Streptomyces clavuligerus. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2007:19
ISBN 978-91-576-7318-3
[Doctoral thesis]

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The discovery of penicillin, a beta-lactam antibiotic, changed the way humans thought about infectious disease. Unfortunately, the widespread use of antibiotics has lead to a concomitant increase in bacterial resistance to these drugs. One of the most common mechanisms of bacterial resistance to beta-lactam antibiotics is mediated through the hydrolysis of the beta-lactam ring by beta-lactamases. In order to combat resistance two strategies have been employed: identification of antibiotics resistant to hydrolysis by beta-lactamases, and the development of beta-lactamase inhibitors. This thesis describes studies on enzymes/proteins in the biosynthetic pathways of beta-lactam antibiotics and beta-lactamase inhibitors. DAOCS is a non-heme Fe(II) dioxygenase that catalyses the oxidative ring expansion of the penicillins to cephalosporins. The expansion of the five-membered penicillin ring to a six-membered cephem ring provides increased resistance to beta-lactamases. The work described here led to the production of crystals with an alternate packing of molecules (belonging to a new space group), which did not show twinning, an anomaly hampering previous structural work. Clavulanic acid is a potent inhibitor of class A bacterial beta-lactamases. CAD is a short chain reductase responsible for the catalysis of the penultimate step in clavulanic acid biosynthesis: the NADPH-dependent reduction of the unstable intermediate clavulanate-9-aldehyde to clavulanic acid. Structures of CAD in complex with the NADPH co-factor, and clavulanic acid, are described here, leading to a proposed reaction mechanism, and an increased understanding of how the enzyme is able to catalyse a reaction involving such a labile intermediate. Approximately half of the genes in the clavulanic acid biosynthesis gene cluster are open reading frames, without a known function. The gene product of Orf15 has been shown to be essential for clavulanic acid production. The structure reported here reveals that it shares similarity with substrate-binding proteins. The complex of ORF15 with L-arginine, a precursor of clavulanic acid, suggests multiple roles for the protein.

Authors/Creators:Mackenzie, Alasdair
Title:Studies on the biosynthetic pathways of clavulanic acid and cephamycin C in Streptomyces clavuligerus
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2007
Number of Pages:91
ALLÖster, L. M., Terwisscha van Scheltinga, A. C., Valegård, K., MacKenzie-Hose, A., Dubus, A., Hajdu, J. & Andersson, I. (2004) Conformational Flexibility of the C terminus with Implications for Substrate Binding and Catalysis Revealed in a New Crystal Form of Deacetoxycephalosporin C synthase. J. Mol. Biol. 343, 157–171 MacKenzie, A. K., Kershaw, N .J., Hernandez, H., Robinson, C.V., Schofield, C.J. & Andersson, I. (2007) Clavulanic Acid Dehydrogenase: Structural and Biochemical Analysis of the Final Steps in the Biosynthesis of the Beta-Lactamase Inhibitor Clavulanic Acid. Biochemistry 46, 1523–1533 Mackenzie, A.K., Caines, M. E. C., Kershaw, N. J., Schofield, C. J., Andersson, I. & Valegård, K. The Crystal Structure of ORF15 from the Clavulanic Acid Biosynthesis Gene Cluster Suggests a Potential Role as a Carrier Protein for Biosynthetic Intermediates. In Manuscript. Johansson M, Mackenzie-Hose A, Andersson I, Knorpp C. (2004) Structure and Mutational Analysis of a Plant Mitochondrial Nucleoside Diphosphate Kinase. Identification of Residues Involved in Serine Phosphorylation and Oligomerization. Plant Physiol. 136, 3034–3042.
Place of Publication:Uppsala
ISBN for printed version:978-91-576-7318-3
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:antibiotics, biosynthesis, streptomyces, cephalosporins, oxidoreductases, arginine, resistance to chemicals
Keywords:beta-lactam antibiotics, Streptomyces clavuligerus, 2-oxoglutarate dependent oxygenase, short chain dehydrogenase, oligopeptide-binding protein, clavulanic acid biosynthesis, protein crystallography, deacetoxycephalosporin C synthase, clavulanic acid dehydrogenase, arginine
Permanent URL:
ID Code:1350
Department:(NL, NJ) > Dept. of Molecular Biology (until 131231)
Deposited By: Alasdair Mackenzie
Deposited On:26 Feb 2007 00:00
Metadata Last Modified:02 Dec 2014 10:11

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