engleski

AUTOCATALYTIC PROCESSING OF ASPARTATE DECARBOXYLASE

AUTOCATALYTIC PROCESSING OF ASPARTATE DECARBOXYLASE Dijana Matak-Vinković,1,3 Mladen Vinković,2,3 Michael Witty,4 Frank von Delft,3 Tom L. Blundell,3 Alison G. Smith4 and Chris Abell5 1Faculty of Science, University of Zagreb, Zvonimirova 8, Zagreb, Croatia 2PLIVA d.d., Prilaz baruna Filipovića 25, Zagreb, Croatia 3Department of Biochemistry, 80 Tennis Court Road, Cambridge CB2 1GA, UK 4Department of Plant Sciences, Downing Street, Cambridge CB2 3EA, UK 5University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK Escherichia coli L-aspartate-a-decarboxylase (ADC), encoded by the gene panD, catalyses the formation of b-alanine from L-aspartate. This is a step in the biosynthetic pathway of pantothenate (vitamin B5). ADC is a (homo)tetramer with its active sites located between adjacent subunits.1 This enzyme is unusual in that its active site contains a covalently bound pyruvoyl group essential for catalysis. The protein is initially translated as an inactive proenzyme (p-protein), which is autocatalytically activated. The maturing process involves a cleavage of a Gly24-Ser25 peptide bond to produce b- and a-chains, as well as transformation of S25 to pyruvoyl. We have now been able to separate and crystallise intermediates and enable a unique insight into the autocatalytic maturing of ADC. _____________ [1] Albert et al., Nature Struct. Biol. 5 (1998) 289-293.

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