Extended Data Fig. 1: Steady-state kinetic analysis of XPK.
From: An ATP-sensitive phosphoketolase regulates carbon fixation in cyanobacteria
a. SeXPK (Vmax 10.8 ± 0.1 µmole mg−1 min−1; Km 19 ± 1.5 mM) is inhibited by 1 or 2 mM of ATP, in the presence of 30 mM phosphate. b. Under the same condition, B. longum XPK (BlXPK) displays no inhibition by ATP. c. SeXPK is not inhibited by phosphate substrate in the presence of saturating F6P (150 mM). d. H706A mutant of SeXPK lost most activity. e. Y710A mutant of SeXPK lost most activity. f. H706R mutant of SeXPK shows only minor effect by ATP. g. ADP does not affect SeXPK activity. The inhibition curve with ATP is included for comparison. h. Methylomonas sp. XPK (MeXPK) is also inhibited by ATP, though to a lesser extent than SeXPK. An enlarged view of the inset is shown in i. Data represent n = 3 individual reactions, mean ± SEM. Each plot represents one of the three experimental repeats.
