Docking study and suggested binding pose of N-terminal glutamine peptide in hNtaq1.

(A) Tripeptides docking study of hNtaq1. Categorized by features of its second residue, the backbone of Ala, Gly, Ile, Leu, Met, Pro, Val tripeptides are colored in yellow, the backbone of Cys, Asn, Gln, Ser, Thr tripetides are colored in green, the His, Lys, Arg tripeptides are colored in blue, the Phe, Trp, Tyr tripeptides are colored in black, and the Asp, Glu tripeptides are colored in orange. (B) The nearest tripeptide in docking study. The substrate-mimicking peptide is shown as green and predicted docking tripeptide Gln-Tyr-Pro is colored in magenta. (C) Binding mode of refined Ser1Gln hNtaq1 mutant on electron density map of hNtaq1. Carbon in substrate-mimicking peptide, catalytic triad, β-strands, loops, and Ser1Gln mutant are colored in green, yellow, cyan, white, and blue, respectively. Oxygen, nitrogen, and sulfur are represented as red, blue, and gold, respectively. Two water molecules are shown as red sphere and electron density map is represented as gray mesh contoured at 2.0 σ.