TY - JOUR
T1 - The structure of 4-hydroxylphenylpyruvate dioxygenase complexed with 4-hydroxylphenylpyruvic acid reveals an unexpected inhibition mechanism
AU - Wang, Xiaoning
AU - Lin, Hongyan
AU - Liu, Junjun
AU - Zhao, Xinyun
AU - Chen, Xi
AU - Yang, Wenchao
AU - Yang, Guangfu
AU - Zhan, Chang guo
N1 - Publisher Copyright:
© 2021
PY - 2021/6
Y1 - 2021/6
N2 - 4-Hydroxyphenylpyruvate dioxygenase (HPPD) is an important target for both drug and pesticide discovery. As a typical Fe(II)-dependent dioxygenase, HPPD catalyzes the complicated transformation of 4-hydroxyphenylpyruvic acid (HPPA) to homogentisic acid (HGA). The binding mode of HPPA in the catalytic pocket of HPPD is a focus of research interests. Recently, we reported the crystal structure of Arabidopsis thaliana HPPD (AtHPPD) complexed with HPPA and a cobalt ion, which was supposed to mimic the pre-reactive structure of AtHPPD-HPPA-Fe(II). Unexpectedly, the present study shows that the restored AtHPPD-HPPA-Fe(II) complex is still nonreactive toward the bound dioxygen. QM/MM and QM calculations reveal that the HPPA resists the electrophilic attacking of the bound dioxygen by the trim of its phenyl ring, and the residue Phe381 plays a key role in orienting the phenyl ring. Kinetic study on the F381A mutant reveals that the HPPD-HPPA complex observed in the crystal structure should be an intermediate of the substrate transportation instead of the pre-reactive complex. More importantly, the binding mode of the HPPA in this complex is shared with several well-known HPPD inhibitors, suggesting that these inhibitors resist the association of dioxygen (and exert their inhibitory roles) in the same way as the HPPA. The present study provides insights into the inhibition mechanism of HPPD inhibitors.
AB - 4-Hydroxyphenylpyruvate dioxygenase (HPPD) is an important target for both drug and pesticide discovery. As a typical Fe(II)-dependent dioxygenase, HPPD catalyzes the complicated transformation of 4-hydroxyphenylpyruvic acid (HPPA) to homogentisic acid (HGA). The binding mode of HPPA in the catalytic pocket of HPPD is a focus of research interests. Recently, we reported the crystal structure of Arabidopsis thaliana HPPD (AtHPPD) complexed with HPPA and a cobalt ion, which was supposed to mimic the pre-reactive structure of AtHPPD-HPPA-Fe(II). Unexpectedly, the present study shows that the restored AtHPPD-HPPA-Fe(II) complex is still nonreactive toward the bound dioxygen. QM/MM and QM calculations reveal that the HPPA resists the electrophilic attacking of the bound dioxygen by the trim of its phenyl ring, and the residue Phe381 plays a key role in orienting the phenyl ring. Kinetic study on the F381A mutant reveals that the HPPD-HPPA complex observed in the crystal structure should be an intermediate of the substrate transportation instead of the pre-reactive complex. More importantly, the binding mode of the HPPA in this complex is shared with several well-known HPPD inhibitors, suggesting that these inhibitors resist the association of dioxygen (and exert their inhibitory roles) in the same way as the HPPA. The present study provides insights into the inhibition mechanism of HPPD inhibitors.
KW - 4-Hydroxyphenylpyruvate dioxygenase
KW - Potential surface scan
KW - QM/MM calculation
KW - Substrate self-inhibition
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U2 - 10.1016/j.cclet.2021.02.041
DO - 10.1016/j.cclet.2021.02.041
M3 - Article
AN - SCOPUS:85101981170
SN - 1001-8417
VL - 32
SP - 1920
EP - 1924
JO - Chinese Chemical Letters
JF - Chinese Chemical Letters
IS - 6
ER -