Fig. 4: Structural and functional analysis of PrfaH.

a Amino acid sequence and secondary structure of ∆14-PrfaH. The α-helices represented as red cylinders and β-strands illustrated as yellow arrows. The amino acids forming the N-terminal domain are highlighted in green, those forming the C-terminal domain are shown in blue, and the amino acids constituting the linker region are represented in gray. b The cartoon illustration and electrostatic potential map of the surface of the ∆14-PrfaH crystal structure. The N-terminal domain is mainly colored green and the C-terminal domain is colored blue. The linker is colored gray. The electrostatic potential map of the ∆14-PrfaH crystal structure is shown in the same orientation as the cartoon illustration. c Analysis of the effect of α1 and α2-α3-β6 on the function of PrfaH. The single amino acid mutation was separately introduced to α1 and α2-α3-β6 by substitution with Ala or Gly. The function of PrfaH mutants was tested via mating assay using pHNYX644∆prfaH. WT represents the conjugation rate of pHNYX644∆prfaH complemented with pHSG575-prfaH(wild type). The others represent the conjugation rates of pHNYX644∆prfaH complemented with pHSG575 expressing PrfaH with a single amino acid mutation at different positions within the α1, α2-α3-β6 regions, respectively. The key residues are shown in the stick representation. Conjugation assays were conducted with n = 3 biological replicates, and statistical analysis was performed using t-test with Welch’s correction. The p-values are shown when making comparisons with the wild-type (WT).