are necessary for the uridylylation of Pn by UTase!UR.In order to elucidate the potential structural changes which may occur upon ligand binding, Pn has been crystallised with a number of effector ligands including 2-ketoglutarate (2-KG), glutamate and ATP, and ATP in combination with 2-ketoglutarate and glutamate. We anticipate that these structure determinations will provide us with new insights into the way Pn influences the enzymes involved in nitrogen regulation and how its interaction with various ligands plays a crucial role in signal transduction.A molecular replacement solution for the Pn/ ATP/2-KG crystals has been obtained and refinement of the structure is in progress. Details of the crystallisation, structure solution and cmTent model will be presented.

No abstract

Die aus L‐Alanin (Ia) über mehrere Stufen in optisch reiner Form zugängliche Hexenopyranosidulose (V) wird in die Verbindungen (VIII), (X) und (XI) umgewandelt.