Figure 1.

Analysis of the N-terminal Tat signal peptide of PtaA and its conserved PLP-binding site, the lysine residue Lys-224. A, depiction of the N-terminal Tat signal peptide of PtaA containing the eponymous twin-arginine motif (ZRRXΦΦ; Z denotes a polar amino acid, R is an l-arginine residue, X is any amino acid, and Φ is a hydrophobic amino acid; Ref. 30). Furthermore, a subsection of the sequence logo of the signal peptide region demonstrates the conserved twin-arginine motif. B, sequence logo of the active-site lysine, Lys-224, and the sequence in its vicinity. The process to generate the sequence logo is detailed under “Experimental procedures.”