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. Author manuscript; available in PMC: 2018 Apr 30.
Published in final edited form as: Biochemistry. 2017 Nov 21;56(48):6368–6376. doi: 10.1021/acs.biochem.7b01027

Figure 6.

Figure 6

More O’Ferrall–Jencks plot for the transition states of phosphoribosyltransferases. PfHGXPRT shows an almost-symmetrical leaving group (pyrophosphate) and attacking nucleophile (hypoxanthine). The PfHGXPRT transition state is closer to the DN + AN corner than other phosphoribosyltransferase transition states. Pauling bond order used a proportionality constant of 0.6 when the bond order is low (>2.0 Å) and 0.3 when the bond is <2.0 Å.29 Organisms: Hs, Homo sapiens; Pf, P. falciparum; St, S. typhimurium. Enzymes: HGXPRT, hypoxanthine-guanine-xanthine phosphoribosyltransferase; NAMPT, nicotinamide phosphoribosyltransferase; OPRT, orotate phosphoribosyltransferase.