Telomere capping proteins are structurally related to RPA with an additional telomere-specific domain

doi:10.1073/pnas.0909203106

Telomere capping proteins are structurally related to RPA with an additional telomere-specific domain

^aDepartment of Chemistry and Biochemistry, University of Colorado, UCB 215, Boulder, CO 80309-0125;
^bMolecular and Cell Biology Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037;
^cDivision of Biological Sciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0376; and
^dBiology Department, Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973-5000

Edited by Elizabeth Blackburn, University of California, San Francisco, CA, and approved October 1, 2009 (received for review August 13, 2009)

Abstract

Telomeres must be capped to preserve chromosomal stability. The conserved Stn1 and Ten1 proteins are required for proper capping of the telomere, although the mechanistic details of how they contribute to telomere maintenance are unclear. Here, we report the crystal structures of the C-terminal domain of the Saccharomyces cerevisiae Stn1 and the Schizosaccharomyces pombe Ten1 proteins. These structures reveal striking similarities to corresponding subunits in the replication protein A complex, further supporting an evolutionary link between telomere maintenance proteins and DNA repair complexes. Our structural and in vivo data of Stn1 identify a new domain that has evolved to support a telomere-specific role in chromosome maintenance. These findings endorse a model of an evolutionarily conserved mechanism of DNA maintenance that has developed as a result of increased chromosomal structural complexity.

Footnotes

¹To whom correspondence should be addressed. E-mail: deborah.wuttke{at}colorado.edu
Author contributions: A.D.G., M.P., F.E.R., and A.H. performed research; A.D.G., M.P., R.T.B., V.L., and D.S.W. analyzed data; and A.D.G., V.L., and D.S.W. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
Data deposition: The atomic coordinates and structure factors have been deposited in the Protein Data Bank, www.rcsb.org [PDB ID code 3K10 (for Stn1-C) and 3K0X (for Ten1)].
This article contains supporting information online at www.pnas.org/cgi/content/full/0909203106/DCSupplemental.