Establishment of a novel covalent enzymatic protein labelling strategy based on a reversible transfer of CDP-choline analogues

An important approach in today’s life sciences is the directed chemical modification of proteins with new functional chemical groups that facilitate the analyses of these biomolecules in vivo and in vitro. However, even functionally diverse proteins consist of the same chemically related building blocks and therefore impair or even prevent a directed and simple modification of proteins by organic-chemical methods due to the sensitive nature of proteins. We will hence establish a novel technique, orthogonal to all currently existing protein labelling strategies. Our approach will combine the creative potential of organic chemistry with the requirements for protein stability. To this purpose, we will exploit the Legionella enzyme AnkX that transfers phosphocholine groups from CDP-choline precursors to protein sequences.

This strategy will exploit the exergonic cleavage of the phosphoanhydrid bond of CDP-choline to conveniently achieve quantitative modification of the target protein. We will synthetically prepare CDP-choline derivatives carrying fluorophores and other interesting chemical functionalities to be transferred to proteins by AnkX. The enzyme AnkX will be functionally optimized by molecular and structural biology approaches and will thus form the basis for a novel protein labelling technique. This system will be developed for the use with purified, native proteins and for the labelling of proteins in living cells. In parallel we will explore the potential of the Legionella enzyme Lem3 that hydrolytically reverses phosphocholination and can thus used for removing the introduced labels on demand.

Christian Hedberg, PhD

Associate Professor, Wallenberg Academy Fellow
Department of Chemistry and Umea Center for Microbial Research
Umea University

Email Dr. Hedberg

Prof. Dr. Aymelt Itzen
Technische Universität München

Tel.: +49 89 289 13343
Fax: +49 89 289 13345

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Publications within the SPP 1623 project

K. Heller, P. Ochtrop, M.F. Albers, F.B. Zauner, A. Itzen, C. Hedberg
Angew. Chem. Int. Ed. 2015, accepted
Covalent protein labeling by enzymatic phosphocholination

D. Wiegandt, S. Vieweg, F. Hofmann, D. Koch, F. Li, Y. Wu, A. Itzen, M.P. Müller, R.S. Goody
Nature Communications 2015, accepted
Locking GTPases covalently in their functional states

C. Hedberg, A. Itzen
ACS Chem. Biol. 2015, 10, 12-21
Molecular perspectives on protein adenylylation.
Link to the article

M.P. Müller, M.F. Albers, A. Itzen, C. Hedberg
ChemBioChem2014, 15(1), 19-26
Exploring Adenylylation and Phosphocholinaton as Post-Translational Modifications
Link to the article

M.F. Albers, C. Hedberg
J. Org. Chem. 2013, 78(6), 2715-2719
Amino Acid Building Blocks for Fmoc Solid-Phase Synthesis of Peptides Phosphocholinated at Serine, Threonine, and Tyrosine
Link to the article