Erskine, P.T. and Senior, N. and Awan, S. and Lambert, R. and Lewis, G. and Tickle, I.J. and Sarwar, M. and Spencer, P. and Thomas, P. and Warren, M.J. and Shoolingin-Jordan, P.M. and Wood, S.P. and Cooper, J.B. (1997) X-ray structure of 5-aminolaevulinate dehydratase, a hybrid aldolase. Nature Structural Biology, 4 (12). pp. 1025-1031. ISSN 1072-8368 .
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5-Aminolaevulinate dehydratase (ALAD) is a homo-octameric metallo-enzyme that catalyses the formation of porphobilinogen from 5-aminolaevulinic acid. The structure of the yeast enzyme has been solved to 2.3 A resolution, revealing that each subunit adopts a TIM barrel fold with a 39 residue N-terminal arm. Pairs of monomers wrap their arms around each other to form compact dimers and these associate to form a 422 symmetric octamer. All eight active sites are on the surface of the octamer and possess two lysine residues (210 and 263), one of which, Lys 263, forms a Schiff base link to the substrate. The two lysine side chains are close to two zinc binding sites one of which is formed by three cysteine residues (133, 135 and 143) while the other involves Cys 234 and His 142. ALAD has features at its active site that are common to both metallo- and Schiff base-aldolases and therefore represents an intriguing combination of both classes of enzyme. Lead ions, which inhibit ALAD potently, replace the zinc bound to the enzyme's unique triple-cysteine site.
|Uncontrolled keywords:||Amino Acid Sequence Animals Binding Sites Crystallography, X-Ray Dimerization Fructose-Bisphosphate Aldolase/chemistry Humans Lysine/chemistry Models, Molecular Molecular Sequence Data Porphobilinogen Synthase/*chemistry/genetics Protein Conformation Protein Structure, Tertiary Saccharomyces cerevisiae/enzymology/genetics Sequence Homology, Amino Acid|
|Divisions:||Faculties > Science Technology and Medical Studies > School of Biosciences|
|Depositing User:||Martin Warren|
|Date Deposited:||20 Oct 2009 08:02|
|Last Modified:||14 Jan 2010 14:42|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/11094 (The current URI for this page, for reference purposes)|
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