Abstract: Sterile alpha motif histidine-aspartate domain protein 1 (SAMHD1) is an enzyme with diverse activities. Its dNTPase activity degrades all canonical dNTPs and many anticancer nucleoside drugs, while its single-stranded nucleic acid binding activity promotes DNA repair and RNA homeostasis in cells. These functions require guanine nucleotide binding to a specific allosteric site (A1) on the enzyme. We previously described how the activities of SAMHD1 could be inhibited in vitro with fragment-based inhibitor design, using dGMP as a targeting fragment for the A1 site. However, these dGMP-tethered inhibitors had poor cell permeability due to the charged guanine monophosphate group. Here, we describe a new approach where the amino form of the guanine acyclic nucleoside acyclovir (NH2- ACV) is used as the targeting fragment, allowing facile coupling to activated carboxylic acids (R?COOH), either directly or using linkers. This approach generates a neutral amide instead of charged monophosphate attachment points. High-throughput screening of a ～375 compound carboxylic acid library identified two compounds (8, 11) with similar micromolar affinities for SAMHD1. Compound 11 was obtained by direct coupling to NH2-ACV, while compound 8 used a five-carbon linker. Both inhibitors had the same dibromonaphthol component from the carboxylic acid library screen. A crystal structure of a complex between SAMHD1 and 8, combined with computational models of bound 11, suggest how the dibromonaphthol promotes binding. The findings establish that guanine-based inhibitors targeting the A1 site do not require nucleotide or cyclic nucleoside structural elements. This guanine site targeting strategy is highly amenable to further chemical optimization.
* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.
t-Butoxycarbonylaminovaleric acid 5-Aminovaleric acid was converted under Schotten-Baumann conditions with di-t-butyl carbonate in the usual manner into the corresponding N-protected acid, melting point 48-50 (from ether/hexane).
With potassium carbonate; In hydrogenchloride; water;
E. 5-guanidinopentanoic acid was prepared by the method of Miller, et al., Synthesis, 777 (1986), which is incorporated herein by reference. 2.00 g of 5-aminovaleric acid was dissolved in a solution of 2.35 g of potassium carbonate in 20 ml of water followed by the portionwise addition of 2.13 g <strong>[1184-90-3]aminoiminomethanesulfonic acid</strong> over 10 minutes. The solid which formed after stirring at room temperature overnight was collected and recrystallized from water. The guanidine was dissolved in dilute hydrochloric acid solution and the solution evaporated in vacuo. The residue was washed with 2-propanol which was then evaporated to give 5-guanidinopentanoic acid hydrochloride.
A mixture of 4-hydroxy-7-phenoxy-isoquinoline-3-carboxylic acid methyl ester (100 mg, 0.34 mmol) and 5-amino-valeric acid (597 mg, 5.1 mmol) in 0.5 N NaOMe in MeOH solution (6.8 mL, 3.4 mmol) was heated to reflux overnight. Reaction mixture was diluted with water (100 mL) and acidified by 1 N HC1 solution to pH = 3-4. Precipitate was collected and rinsed with water. It was dried in vacuo to provide the title compound (102 mg, 0.27mmol) in 80% yield. LC-MS ESI-: 379.07 (M-l)
Chemistry
Pharmaceutical Intermediates
Inhibitors/Agonists
Material Science
For Research Only
120K+ Compounds
Competitive Price
1-2 Day Shipping
