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Biophysics in the Understanding, Diagnosis, and Treatment of Infectious Diseases Poster Abstracts
87
11-POS
Board 11
NMR Characterization of the Natively Unfolded N-Terminus and the Redox-Sensitive
Rubredoxin Motif of Mycobacterial Protein Kinase C–A Tuberculosis Drug Target
Sonja Alexandra Dames
1,2
, Matthias Wittwer
1
.
1
Technische Universtiät München, Garching, Bavaria, Germany,
2
Helmholtz Zentrum München,
Neuherberg, Bavaria, Germany.
Protein kinase G (PknG) is a eukaryotic-like ser/thr kinase blocking the degradation of
pathogenic organisms such as Mycobacterium tuberculosis within host macrophages. Because
PknG is secreted into the host cytosol, it is an ideal target for tuberculosis drugs since they do not
have to pass the only low permeable mycobacterial cell wall.
The catalytic ser/thr kinase domain (
∼
147-390) is N-terminally flanked by a rubredoxin-like
metal-binding motif (RD,
∼
74 –147) and C-terminally by a tetratricopeptide repeat domain
(TPRD). The N-terminal 73 residues are intrinsically disordered (NORS) and harbor the only site
(T63) phosphorylated in vivo
1
. Both, deletions or mutations in the NORS or the redox-sensitive
RD significantly decrease PknG-mediated mycobacterial survival in the host
1,2
. It has been
shown that PknG is more active in the presence of an oxidizing agent
1
. Here, we present the
NMR characterization of the NORS region and its chemical shift assignment as well as of the
redox-regulated un- and refolding of the RD and its ability to interact with membrane mimetics.
The NMR data is complemented by standard kinase assays. Based on our data controlled
unfolding of the RD by oxidization may regulate the kinase activity. The detected membrane
mimetic interactions may play a role for PknG localization.
References:
1. Tiwari, D., Singh, R. K., Goswami, K., Verma, S. K., Prakash, B., and Nandicoori, V. K.
(2009). J Biol. Chem. 284, 27467-27479.
2. Scherr, N., Honnappa, …, Pieters, J., and Steinmetz, M. O. (2007). Proc. Natl. Acad. Sci. U S
A 104, 12151-12156.
Acknowledgments: We thank the group of Prof. Dr. J. Pieters from the Biozentrum Basel for
fruitful collaboration activities. The project is funded by the German Research Foundation
(collaborative research center 1035, project B04).