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Posttranslationale Modifikationen in Prokaryonten, EF-Tu

Projektleiterin: Corinna Lippmann, Tel. +49 30 838-6003
Fax. +49 30 838-6403, E-mail: pollux@chemie.fu-berlin.de
Institut für Biochemie, Thielallee 63, 14195 Berlin

Co-workers: Thomas Plath, Boris Radau, Patrick Schneider



Keywords: Protein biosynthesis, posttranslational modifications, protein-RNA interactions

Corinna Lippmann a postdoc of Prof. V. A. Erdmann's group has chosen a central protein of the elongation cycle of protein biosynthesis for her studies on posttranslational modifications in prokaryotes. The subject of interest, the elongation factor Tu (EF-Tu) carries two to three modifications, depending on growth - or activity state. One of the reversible modifications, the phosphorylation was described for the first time by Dr. Lippmann.
Several experimental results indicate that the phosphorylation is part of the elongation cycle of protein biosynthesis. The strictly conserved position, threonine 382 in E.coli is located at a crucial point in the interface between the first and third domain of the three-domain protein. Introduction of a phosphate group leads to a switch of the condensed (GTP-complexed) formation to the more open GDP form. Both structures are known at high resolution since Corinna Lippmann first succeeded in growing crystals from the intact protein suitable for X-ray analysis.
The investigations comprise methods in protein biochemistry and molecular biology. The working group consists of two Ph.D. students and one master student. Frequently postdocs from other European countries are joining the group of Corinna Lippmann. The studies on the EF-Tu project are supported by the DFG (Li 611 1/2) and the European Community.
Furthermore Corinna Lippmann is involved in a trilateral project between Israel, the Palestinian Authority and Germany, initiated and coordinated by Prof. V. A. Erdmann concerned with tumour diagnosis and therapy based on oncofetal RNAs.

Selected publications:

Lippmann C., Lindschau C. & Erdmann V.A. (1992)
Thin-layer electrophoresis with PhastSystem facilitates analysis of phosphoamino acids from proteins bound to Immobilon.
Electrophoresis, 13, 666-668

Lippmann C., Lindschau C., Vijgenboom E., Schröder W., Bosch L. & Erdmann V.A. (1993)
Prokaryotic elongation factor is phosphorylated in vivo.
J.Biol.Chem., 268, 601-607

Abdel-Rahim E., Ahmed F.A., Abdel-Fatah O.M., Erdmann V.A. & Lippmann C. (1995)
The changes of protein patterns during one week of germination of some legume seeds and roots.
Food Chemistry, 52, 433-437

Alexander C., Mesters J.R., Kraal B., Bilgin N., Hilgenfeld R., Lindschau C., Erdmann V.A. & Lippmann C. (1995)
Phosphorylation of EF-Tu prevents ternary complex formation.
J.Biol.Chem. 270, 14541-14547

Polekhina G., Thirup S., Kjeldgaard M., Nissen P., Lippmann C. & Nyborg J. (1996)
Crystal structure of intact elongation factor Tu in complex with GDP. submitted


Corinna Lippmann, pollux@chemie.fu-berlin.de