Figure 1

Orthogonal views of the compact and extended tetrameric configurations seen in the crystal structures of full length LTTRs.
(a) The domain structure of LTTR monomers. Major elements are labelled. (b) The crystal structure of CbnR14 showing LTTR homotetramers (each monomer coloured differently) in a compact configuration. The position of one of the wHTH dimers that flank the central tetrameric RD core is highlighted. (c) The crystal structure of TsaR7 showing LTTR homotetramers in an extended configuration. (d) The current hypothesis is that activation of LTTRs leads to a change in conformation from compact to expanded homotetrameric configurations.