Sequence-dependent DNA flexibility is an important structural property 
originating from the DNA 3D structure. In this paper, we investigate the DNA 
flexibility of the budding yeast (S. Cerevisiae) replication origins on a 
genome-wide scale using flexibility parameters from two different models, the 
trinucleotide and the tetranucleotide models. Based on analyzing average 
flexibility profiles of 270 replication origins, we find that yeast replication 
origins are significantly rigid compared with their surrounding genomic regions. 
To further understand the highly distinctive property of replication origins, we 
compare the flexibility patterns between yeast replication origins and 
promoters, and find that they both contain significantly rigid DNAs. Our results 
suggest that DNA flexibility is an important factor that helps proteins 
recognize and bind the target sites in order to initiate DNA replication. 
Inspired by the role of the rigid region in promoters, we speculate that the 
rigid replication origins may facilitate binding of proteins, including the 
origin recognition complex (ORC), Cdc6, Cdt1 and the MCM2-7 complex.