Communication
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remained unmodified, while significant changes were observed
in stearoylethanolamide (SEA) (Fig. S7b, ESI†).
In conclusion, the present report describes the identification
of the quinazoline sulfonamide derivative, 18 (ARN19874), as
the first inhibitor of intracellular NAPE-PLD activity.
This work was partially supported by the NIH grant DA012413
(to D. P.). D. Piomelli ideated and directed the project; B. C.
designed, performed and analyzed in vitro experiments; E. D.,
D. P. and P. T. designed and performed chemical syntheses;
M. M., S. R. and M. M. ideated and performed in silico experi-
ments; N. R. designed and performed cell experiments; P. M. and
G. G. generated of one protein mutant and provided crystallo-
graphic information; T. B. performed chemical syntheses; D. P.
wrote the manuscript along with M. M. and B. C.
Fig. 4 (a) Docking solution for 18 in NAPE-PLD active site. (b) 18 assumed a
similar pose with Q320S NAPE-PLD. (c) IC50 of 18 with Q320A or (d) Q320S
NAPE-PLD mutants.
Conflicts of interest
confirming that glutamine 320 plays a significant role in sup-
porting catalysis.2 The residual activity was sufficient, however,
to investigate the effects of compound 18. The compound was
significantly less potent on the Q320A mutant (IC50 = 89.2 Æ 2.3 mM,
n = 3) than on wild-type NAPE-PLD (IC50 = 46.2 Æ 1.6 mM, n = 3)
(Fig. 4c), which is suggestive of a role for glutamine 320 in the
inhibitory effects of 18. Interestingly, mutating glutamine
320 to serine (Fig. 4b) did not significantly affect inhibition
(36.7 Æ 1.6 mM in Q320S NAPE-PLD, n = 3) (Fig. 4d), suggesting
that serine may substitute for glutamine in the interaction with
18. We interpret the results of these studies as indicating
that 18 inhibits NAPE-PLD activity by binding to the diatomic
zinc center of the enzyme, via its sulfonamide moiety, and to
glutamine 320, via its quinazolinedione ring.
There are no conflicts to declare.
Notes and references
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Chem. Commun.
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