STRUCTURE AND FUNCTION OF HEME BIOSYNTHETIC ENZYMES

Martina Jahn, Ilka Heinemann & Dieter Jahn

 

Institute of Micorbiology, Technical University Braunschweig, Spielmannstr,7, D 38106 Braunschweig, Germany, m.jahn@tu-bs.de

 

 

The initial step of heme biosynthesis in humans, animals, fungi and a few bacteria is catalyzed by aminolevulinic acid synthase. The solved crystal structure of the enzyme in complex with substrates and cofactor explains in molecular detail the enzymatic mechanism and the surprising structural basis of various enzyme defects causing X-linked sideroblastic anemia. Furthermore, the two enzymes catalyzing the steps prior iron insertion, coproporphyrinogen III and protoporphyrinogen IX oxidase, were investigated for their structure-function relationsship. Data concernng the molecular basis of their catalytic mechanisms will be presented. Finally, an outlook concerning the application of heme biosynthetic enzymes in the treatment of maleria in our laboratory will be given.