The yeast polymerase suppressor 1 (PSP1) protein partially suppresses mutations in DNA polymerases α and delta [1]. The C-terminal half of PSP1 contains a domain, which is also found in several hypothetical proteins from both eukaryotic and prokaryotic sources:

• Crithidia fasciculata RBP45 and RBP33, subunits of the cycling sequence binding protein (CSBP) II. RBP45 and RBP33 proteins bind specifically to the cycling sequences present in several mRNAs that accumulate periodically during the cell cycle. RBP45 and RBP33 are phosphoproteins, which are phosphorylated differentially during progression through the cell cycle. Hypothetical proteins with high sequence similarity have been identified in other kinetoplastid organisms [2].
• Bacillus subtilis yaaT protein, which plays a significant role in phosphorelay during initiation of sporulation. It is possible that the yaaT protein is also related to DNA replication. The sequence of the yaaT protein is widely conserved in prokaryotes (bacteria and archaea), but the functions of the protein are unknown [3].

The actual biological significance of the PSP1 C-terminal domain has not yet been clearly established.

The profile we developed covers the entire PSP1 C-terminal domain.