Fig. 5

BBR binds with the human enzymes hsMTHFD1 and hsMTHFD1L. A The proteins with the activity of formate-THF ligase in different organisms. In E. coli, there is no protein with the activity of formate-THF ligase, while in several other bacteria such as Streptococci, FtfL displays the activity of formate-THF ligase. In humans, there are different enzymes in the cytoplasm and the mitochondrion, respectively. In the cytoplasm, MTHFD1 exerts formate-THF ligase, 5,10-methenyl-THF cyclohydrolase, and 5,10-methylene-THF dehydrogenase functions. In the mitochondrion, MTHFD1L plays the same role as FtfL. B, C BBR directly binds hsMTHFD1 and hsMTHFD1L. The binding affinities (Kd) were determined by fitting the binding data to a kinetics 1:1 binding model. D, E Effect of BBR on hsMTHFD1 and hsMTHFD1L enzymatic activities. Data are presented as the mean ± S.D. of three independent replicates. The one-way ANOVA with Tukey’s multiple comparison test was used for statistical analysis, *p < 0.05, **p < 0.01, ***p < 0.001