Crystal structure of the human Pax6 paired domain-DNA complex reveals specific roles for the linker region and carboxy-terminal subdomain in DNA binding.Xu, H.E., Rould, M.A., Xu, W., Epstein, J.A., Maas, R.L., Pabo, C.O.
(1999) Genes Dev 13: 1263-1275
- PubMed: 10346815
- DOI: https://doi.org/10.1101/gad.13.10.1263
- Primary Citation of Related Structures:
- PubMed Abstract:
Pax6, a transcription factor containing the bipartite paired DNA-binding domain, has critical roles in development of the eye, nose, pancreas, and central nervous system. The 2.5 A structure of the human Pax6 paired domain with its optimal 26-bp site reveals extensive DNA contacts from the amino-terminal subdomain, the linker region, and the carboxy-terminal subdomain. The Pax6 structure not only confirms the docking arrangement of the amino-terminal subdomain as seen in cocrystals of the Drosophila Prd Pax protein, but also reveals some interesting differences in this region and helps explain the sequence specificity of paired domain-DNA recognition. In addition, this structure gives the first detailed information about how the paired linker region and carboxy-terminal subdomain contact DNA. The extended linker makes minor groove contacts over an 8-bp region, and the carboxy-terminal helix-turn-helix unit makes base contacts in the major groove. The structure and docking arrangement of the carboxy-terminal subdomain of Pax6 is remarkably similar to that of the amino-terminal subdomain, and there is an approximate twofold symmetry axis relating the polypeptide backbones of these two helix-turn-helix units. Our structure of the Pax6 paired domain-DNA complex provides a framework for understanding paired domain-DNA interactions, for analyzing mutations that map in the linker and carboxy-terminal regions of the paired domain, and for modeling protein-protein interactions of the Pax family proteins.
Department of Biology and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 USA.