Dataset for: Characterization of a Polypeptide Binding Site in the DEAD Motor of the SecA ATPase

Peptides from a CNBr digest of signal-sequenceless maltose binding protein (MBP) were coupled to a surface plasmon resonance (SPR) chip. SecA-N95, SecA-N68, and SecA-DM (which consists of only the DEAD Motor domains, NBD1 and NBD2) bound to the immobilized peptides; ADP weakened the binding. SecA-DM, which lacks the “preprotein cross-linking domain” (PPXD), displayed the most extensive binding, while an MBP-PPXD chimera showed no binding, demonstrating that the PPXD does not contribute to the binding. The sequence specificity was characterized using oriented peptide libraries; these results enabled synthesis of a 20-residue peptide that was used to recapitulate the results obtained with MBP-derived peptides. The study shows there is a promiscuous and nucleotide-modulated peptide-binding site in the DEAD Motor domains of SecA.