Abstract
The oncogenic transcription factor Myc is one of the most interesting members of the basic-helix-loop-helix-zipper (bHLHZip) protein family. Deregulation of Myc via gene amplification, chromosomal translocation or other mechanisms lead to tumorigenesis including Burkitt lymphoma, multiple myeloma, and many other malignancies. The oncogene myc is a highly potent transforming gene and capable to transform various cell types in vivo and in vitro. Its oncogenic activity initialized by deregulated expression leads to a shift of the equilibrium in the Myc/Max/Mad network towards Myc/Max complexes. The Myc/Max heterodimerization is a prerequisite for transcriptional functionality of Myc. Primarily, we are focusing on the apo-state of the C-terminal domain of v-Myc, the retroviral homolog of human c-Myc. Based on multi-dimensional NMR measurements v-Myc appears to be neither a fully structured nor a completely unstructured protein. The bHLHZip domain of v-Myc does not exist as a random coil but exhibits partially pre-formed α-helical regions in its apo-state. In order to elucidate the structural propensities of Myc in more detail, the backbone and side-chain assignments obtained here for apo-Myc are a crucial prerequisite for further NMR measurements.