Fig. 3: Structural features and catalytic activities of PSMα3 variants.
From: Staphylococcus aureus functional amyloids catalyze degradation of β-lactam antibiotics
a Sequences of the PSMα3 variants. The modified residues in the variants are marked purple. α3-cationic: all acidic residues and the Asn-22 in the C-terminus were amidated. α3-F10P:Phe-10 was replaced with Pro residue. α3-(d)FF: two D-Phe residues instead of the L-handed residues. α3-EG/K: amine sidechains in the Lys residues were capped with two units of ethylene-glycol. b Cryo-TEM images of the PSMα3 variants (concentrations of 300 µM). Bars correspond to 100 nm. The experiment was repeated three times with independent peptide samples. c Amide region FTIR spectra (vertical broken lines represent the values of 1684 cm−1, 1650 cm−1, and 1628 cm−1). d CD spectra of the PSMα3 variants. e Nitrocefin degradation reaction kinetics in the presence of PSMα3 variant assemblies formed after 2-h incubation in DIW and addition of Hepes buffer (peptide concentrations were 170 µM, initial nitrocefin concentration 107 µM). f Initial degradation rates, V0, at initial nitrocefin concentration of 107 µM. Data presented in box-and-whisker plot, with mean line and quartile calculation using inclusive median, NPSMα3 = 14, Nα3-cationic = 9, Nα3-cationic = 8, Nα3-(d)FF = 9, Nα3-scrambles = 8, Nα3-EG/K = 9. The same color-coding was used in panels c-f. Source data are provided as a Source Data file.
