BZIP proteins

Some purely major groove-binding TFs, such as the basic-region leucine zipper (bZIP) protein GCN4, can co-occupy the DNA helix in the presence of polyamides [72]. Modified polyamides with an attached Arg-Pro-Arg tripeptide can interfere with major groove-binding proteins by disrupting key phosphate contacts, distort-... 

Bremer, R. E., N.R. Wurtz, J.W. Szewc-ZYK, and P.B. Dervan. Inhibition of major groove DNA binding bZIP proteins by positive patch polyamides. Bioorg. 

Our laboratory started to work on circadian rhythms by serendipity, while studying the liver-specific transcription of the serum albumin gene. We isolated a cDN A copy for a transcription factor that we dubbed DBP (for albumin promoter D-element Binding Protein). DBP, a basic leucine zipper (bZip) transcription factor, is the founding member of the PAR (proline-acidic amino acid rich)-domain bZip transcription factors, a small subfamily of bZip proteins consisting of DBP, TEF and HLF. It turned out that DBP protein and mRNA accumulation undergo circadian cycles with amplitudes in excess of one hundred-fold (Wuarin Schibler 1990). 

Chattopadhyay, S. et al., Arahidopsis bZIP protein HY5 directly interacts with light-responsive promoters in mediating light control of gene expression. Plant Cell, 10, 673, 1998. 

Fig. 5. (a) A bZIP protein dimer showing the leucine zipper dimerization domain and the two basic domains (b) folded structure of a bZIP protein showing the basic domains binding in the major groove of the target DNA. Reprinted from A. Travers, DNA-Protein Interactions, Chapman Hall, 1993. With permission from A. Travers. 

Abe, M., Kobayashi, Y., Yamamoto, S., Daimon, Y., Yamaguchi, A., Ikeda, Y., Ichinoik, H., Notaguchi, M., Goto, K., and Araki, T., FD, a bZIP protein mediating signals from the floral pathway intergrator FT at the shoot apex, Science, 309, 1052-1056, 2005. 

Peptide Models of bZIP Proteins Quantitative Analysis of DNA Affinity and Specificity... 

Calculations. It has not been established whether all bZIP proteins bind DNA as pre-assembled dimers in a single step or whether two protein monomers bind sequentially with dimerization occurring on the DNA. If dimerization precedes DNA binding, the binding reaction will be described by scheme 1 ... 

As mentioned above, the bZIP proteins function as dimers in order to bind to DNA. Presently, there is no conclusive evidence to indicate whether Nrf2 may activate gene expression as a homodimer or whether it is obligated to form heterodimeric complexes. Because p45 NF-E2, the first family member of these proteins, was found to dimerize with MafK in order to bind DNA and activate transcription (56), it was hypothesized that small Maf proteins may represent a partner for Nrf2 in effecting transcriptional activation (52). 

The bZIP protein family is the third prominent group of TFs playing a vital role in PDR. Of the several YAP genes in yeast, the basic leucine zipper transcription factors Yapl, Yap2, and Yap8 are linked to oxidative stress response [98,120], vacuolar detoxification, and heavy metal tolerance. 

Wu, A., Wemmie, J.A., Edgington, N.P., Goebl, M., Guevara, J.L., and Moye-Rowley, W.S. (1993) Yeast bZip proteins mediate pleiotropic drug and metal resistance. The Journal of Biological Chemistry, 268, 18850-18858. 

The second class of eukaryotic DNA-binding unit is the basic-leucine zipper, or bZip, proteins (Figure 31.6). This DNA-binding unit consists of a pair of long a helices. The first part of each a helix is a basic region that lies in the major groove of the DNA and makes contacts responsible for DNA-site recognition. The second part of each a helix forms a coiled-coil structure with its partner. Because these units are often stabilized by appropriately spaced leucine residues, these structures are often referred to as leucine zippers (p. 45). 

Paolella, D. N. Palmer, C. R. Schepartz, A. DNA targets for certain bZIP proteins distinguished by an intrinsic bend. Science 1994 264 1130-1133. 

Other c(5-elements involved in ABA induced transcription are a seed-specific element which mediates induction by ABA of the Cl gene in maize endosperm [33], an element from the promoter of the C. plantagineum gene CDeT27-45 [60] and the TT motif (TTTCGTGT) from the DCS gene from carrot [43,86]. The TT motif can be viewed as an imperfect ABRE and two bZIP proteins that bind to the element have been cloned. 

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