Structural Basis for the Selective Binding of Inhibitors to 6-Hydroxymethyl-7,8-dihydropterin Pyrophosphokinase from Staphylococcus aureus and Escherichia coli.
6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) is a member of the folate biosynthesis pathway found in prokaryotes and lower eukaryotes that catalyzes the pyrophosphoryl transfer from the ATP cofactor to a 6-hydroxymethyl-7,8-dihydropterin substrate. We report the chemical synthesis of a series of S-functionalized 8-mercaptoguanine (8MG) analogues as substrate site inhibitors of HPPK and quantify binding against the E. coli and S. aureus enzymes (EcHPPK and SaHPPK). The results demonstrate that analogues incorporating acetophenone-based substituents have comparable affinities for both enzymes. Preferential binding of benzyl-substituted 8MG derivatives to SaHPPK was reconciled when a cryptic pocket unique to SaHPPK was revealed by X-ray crystallography. Differential chemical shift perturbation analysis confirmed this to be a common mode of binding for this series to SaHPPK. One compound (41) displayed binding affinities of 120 nM and 1.76 μM for SaHPPK and EcHPPK, respectively, and represents a lead for the development of more potent and selective inhibitors of SaHPPK.
Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia.|CSIRO Biosciences Program , Parkville, Victoria 3052, Australia.
Matthew L
ML
Dennis
Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia.
Noel P
NP
Pitcher
Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia.
Michael D
MD
Lee
Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia.
Aaron J
AJ
DeBono
Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia.|State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University , Nanjing 210093, People's Republic of China.
Zhong-Chang
ZC
Wang
Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia.
Jitendra R
JR
Harjani
Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia.
Raphaël
R
Rahmani
Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia.
Ben
B
Cleary
CSIRO Biosciences Program , Parkville, Victoria 3052, Australia.
Thomas S
TS
Peat
Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia.
Jonathan B
JB
Baell
Monash Institute of Pharmaceutical Sciences, Monash University , Parkville, Victoria 3052, Australia.
James D
JD
Swarbrick
D001665:Binding Sites / Q000187:drug effects; D018360:Crystallography, X-Ray; D017854:Diphosphotransferases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D004926:Escherichia coli / Q000201:enzymology*; D008958:Models, Molecular; D015394:Molecular Structure; D013211:Staphylococcus aureus / Q000201:enzymology*; D013329:Structure-Activity Relationship
D004791:Enzyme Inhibitors; D017854:Diphosphotransferases; C019684:2-amino-4-hydroxy-6-hydroxymethyldihydropteridine pyrophosphokinase