Figure 6: Lar accessory proteins.
From: Lactate racemase is a nickel-dependent enzyme activated by a widespread maturation system
(a) Ni content of Lar proteins as measured by PAR assays and ICP-AES. PAR data are average of two independent experiments (triplicates in each experiment). ICP-AES data are average of duplicates from one experiment. (b) Specific Lar activity of purified proteins and in vitro activation of apo-LarA. ALpNiBCE, LarA purified from a Lc. lactis strain expressing LarBCE and cultivated in the presence of Ni(II); ALpNiΔBCE, LarA purified from a Lc. lactis strain not expressing LarBCE and cultivated in the presence of Ni(II); +ENiBC, assay performed in the presence of an excess of LarE purified from a Lc. lactis strain expressing LarBC and cultivated in the presence of Ni(II); +EBC, assay performed in the presence of an excess of LarE purified from a Lc. lactis strain expressing LarBC and cultivated in the absence of Ni(II); +ENiΔBC, assay performed in the presence of an excess of LarE purified from a Lc. lactis strain not expressing LarBC and cultivated in the presence of Ni(II); BNi, LarB purified from a Lc. lactis strain cultivated in the presence of Ni(II); and CNi, LarC purified from a Lc. lactis strain cultivated in the presence of Ni(II). Data are average of quadruplicates from one representative experiment of two independent experiments showing similar results. L-lactate was used as a substrate for all Lar activity measurements. The error bars represent the 95% confidence interval (Student’s t-test) in a and b.
