Chemical shift assignments of the homodimer protein SP_0782 (7-79) from Streptococcus pneumoniae.

The protein SP_0782 from Streptococcus pneumonia is a small homodimeric protein that belongs to a protein family containing representative members with single-stranded DNA (ssDNA) binding functions. The ssDNA binding of the homolog YdbC from Lactococcus lactis was previously characterized when bound to a 20-mer of pyridine-rich ssDNA, sharing an overall similar structural fold with the human transcription coactivator PC4. We report that SP_0782 exhibits distinct differences in ssDNA binding properties from YdbC as revealed by NMR titration experiments. Unlike the binding of the ssDNA dT19G1 to PC4 and YdbC, SP_0782 resulted in aggregation. In addition, SP_0782 exhibits favorable binding to shorter ssDNA such as dT6. The reason is unclear, and the SP_0782 structure-function relationship remains to be elucidated. Here, we report the complete (1)H, (13)C, and (15)N backbone and side chain NMR assignments of SP_0782, residues 7-79.