Rap1 (repressor-activator protein 1) from Saccharomyces cerevisiae, containing a BRCT domain at its N-terminus, is a multifunctional protein that controls telomere function, silencing, and the activation of glycolytic and ribosomal protein genes. In this work, we determined the solution structure of Rap1 BRCT domain, which contains three beta-strands and three alpha-helices. Structural comparison indicated that Rap1 BRCT domain adopts a global fold similar to other BRCT domains, implying some common structural aspects of BRCT domain family. On the other hand, Rap1 BRCT domain displays structural characteristics significantly different from other BRCT domains in that Rap1 BRCT domain adopts a rather flexible conformation with less secondary structure elements, revealing a novel fold of the BRCT domain family. Crown Copyright (C) 2010 Published by Elsevier Inc. All rights reserved.