TABLE 2.

Mass spectrometry of affinity-purified Orf20-His₆ shows that the HelP homologues are associated with the relaxase

Protein	% sequence coveragea	No. of peptidesb	Molecular size (kDa)c
Orf20 relaxase	51.5	84	46.8
Orf22 HelP	67.2	33	14.1
Orf23 HelP	69.6	18	11.8

^aPercentage of the protein sequence detected by mass spectrometry. Amino acid sequences were based on Tn916 genes (GenBank accession no. U09422.1, except that for Orf20, which was based on the reannotated gene starting at CUG and encoding the N-terminal helix-turn-helix region (Fig. 3B).

^bNumber of total peptides detected.

^cPredicted molecular size.