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]
![]() |
PDF
7MB |
Abstract
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 | ||||
Year of publishing : | 2007 | ||||
Number: | 2007:19 | ||||
Number of Pages: | 91 | ||||
Papers/manuscripts: |
| ||||
Place of Publication: | Uppsala | ||||
ISBN for printed version: | 978-91-576-7318-3 | ||||
ISSN: | 1652-6880 | ||||
Language: | English | ||||
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 | ||||
URN:NBN: | urn:nbn:se:slu:epsilon-1485 | ||||
Permanent URL: | http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-1485 | ||||
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 |
Repository Staff Only: item control page