The solution structure and backbone dynamics of the transcriptional ac
tivator PUT3 (31-100) has been characterized using NMR spectroscopy. P
UT3 (31-100) contains three distinct domains: a cysteine zinc cluster,
linker, and dimerization domain, The cysteine zinc cluster of PUT3 cl
osely resembles the solution structure of GAL4, while the dimerization
domain forms a long coiled-coil similar to that observed in the cryst
al structures of GAL4 and PPR1. However, the residues at the N-termina
l end of the coiled-coil behave very differently in each of these prot
eins. A comparison of the structural elements within this region provi
des a model for the DNA binding specificity of these proteins. Further
more, we have characterized the dynamics of PUT3 to find that the zinc
cluster and dimerization domains have very diverse dynamics in soluti
on. The dimerization domain behaves as a large protein, while the peri
pheral cysteine zinc clusters have dynamic properties similar to small
proteins.