PLENARYLECTURES 79

PLO4 NOVEL ASPECTS OF COPPER (AZURIN AND

ASCORBATE OXIDASE) AND ZINK PROTEINS

(PR~CARBOXYPEPTIDASE) AND THE

STRUCTURE OF A CALCIUM, MEMBRANE

BINDING PROTEIN (ANNEXIN). Robert Huber, Max-Planck-Institut fiir Biochemie, Am Klopferspitz, D-8033 Martinsried

Refinement of ascorbate oxidase (AO) revealed details of the trinuclear copper site which help to explain its spectroscopic properties. Modelling by homology on the basis of the structure of A0 lead to detailed and topological models of the lactase and cer loplasmin, respectively (1, 2). The first refinement of wild-type and mutant azurins of Pseudomonas aeruginosa clarifies the role of specific residues (His37) in electron transfer (3). The crystal structure analysis of pancreatic procarboxypeptidase revealed the mechanism of inactivation of the enzyme by the pro-part through occlusion of the substrate binding site (4). Annexins are a superfamily of ubiquitous, intracellular proteins with quite diverse cellular functions and a common property of calcium induced membrane binding. When bound to membranes, some members form voltage-gated ion channels. The high resolution crystal structure of annexin V led to the detailed molecular structure and definition of the calcium and lanthanum (which is a channel blocker) binding sites and allows a view at atomic resolution of an ion channel (5, 6, 7).

1. A.Messerschmidt, A.Rossi, R. Ladenstein, R. Huber, M. Bolognesi, G. Gatti, A.Marchesini, R. Petruzzelli and A. J. Finazzi-Agr6. J.Mol. Biol., 206, 513-529 (1989)

2. A.Messerschmidt & R.Huber. Eur. J. Biochem., 187, 341- 352. (1990).

3. H.Nar, A. Messerschmidt, R. Huber, M. van de Kamp and G.W. Canters. J. Mol. Biol., 218, in press.

4. M.Coll, A.Guasch, F.X. Avilds and R. Huber. The EMBO Journal, 10, l-9 (1991).

5. R. Huber, J. RBmisch and E. Paques. The EMBO Journal, 9, 3867-3874 (1990).

6. R. Huber, M. Schneider, I. Mayr, J. Rijmisch and E. Paques. FEBS Letters, 275, 15-21. (1990).

7. A. Brisson, G. Mosser and R. Huber. J. Mol. Biol. (1991). Submitted.