Fig. 1

SsRidA has 2AA deaminase activity in vitro. Increased pyruvate formation in reactions containing SsRidA indicates that SsRidA is capable of catalyzing 2AA deamination. Each coupled assay contained NADH (0.25 mM), PLP (30 µM), 5LDH (5 U per 300 μl reaction), and CdsH (0.19 μM) in 100 mM Tris–HCl (pH 8.0). RidA proteins (SeRidA or SsRidA) were present at 0.27 μM when indicated. Reactions were performed in triplicate in a 96-well quartz plate and were initiated with addition of L-cysteine at varying concentrations. The plate was shaken for 5 s before first read. The rate of pyruvate formation was calculated using Beer’s law, the extinction coefficient of NADH (6220 M⁻¹ cm⁻¹), and the absorbance at 340 nm from 0 to 30 s. Graph was constructed in Prism 9 (GraphPad). Error bars represent standard deviation.