Defining the structural requirements for ribose 5-phosphate-binding and intersubunit cross-talk of the malarial pyridoxal 5-phosphate synthase.

Bianca Derrer, Volker Windeisen, Gabriela Guédez Rodríguez, Joerg Seidler, Martin Gengenbacher, Wolf D Lehmann, Karsten Rippe, Irmgard Sinning, Ivo Tews, Barbara Kappes

Index: FEBS Lett. 584(19) , 4169-74, (2010)

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Abstract

Most organisms synthesise the B(6) vitamer pyridoxal 5-phosphate (PLP) via the glutamine amidotransferase PLP synthase, a large enzyme complex of 12 Pdx1 synthase subunits with up to 12 Pdx2 glutaminase subunits attached. Deletion analysis revealed that the C-terminus has four distinct functionalities: assembly of the Pdx1 monomers, binding of the pentose substrate (ribose 5-phosphate), formation of the reaction intermediate I(320), and finally PLP synthesis. Deletions of distinct C-terminal regions distinguish between these individual functions. PLP formation is the only function that is conferred to the enzyme by the C-terminus acting in trans, explaining the cooperative nature of the complex.Copyright © 2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.