Structure-activity relationships of 7-deaza-6-benzylthioinosine analogues as ligands of Toxoplasma gondii adenosine kinase.
Several 7-deaza-6-benzylthioinosine analogues with varied substituents on aromatic ring were synthesized and evaluated against Toxoplasma gondii adenosine kinase (EC.2.7.1.20). Structure-activity relationships indicated that the nitrogen atom at the 7-position does not appear to be a critical structural requirement. Molecular modeling reveals that the 7-deazapurine motif provided flexibility to the 6-benzylthio group as a result of the absence of H-bonding between N7 and Thr140. This flexibility allowed better fitting of the 6-benzylthio group into the hydrophobic pocket of the enzyme at the 6-position. In general, single substitutions at the para or meta position enhanced binding. On the other hand, single substitutions at the ortho position led to the loss of binding affinity. The most potent compounds, 7-deaza- p-cyano-6-benzylthioinosine (IC 50 = 5.3 microM) and 7-deaza- p-methoxy-6-benzylthioinosine (IC 50 = 4.6 microM), were evaluated in cell culture to delineate their selective toxicity.
Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, USA.
Young Ah
YA
Kim
Ashoke
A
Sharon
Chung K
CK
Chu
Reem H
RH
Rais
Omar N
ON
Al Safarjalani
Fardos N M
FN
Naguib
Mahmoud H
MH
el Kouni
D000248:Adenosine Kinase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000818:Animals; D000981:Antiprotozoal Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D002478:Cells, Cultured; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D047428:Protein Kinase Inhibitors / Q000031:analogs & derivatives / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013868:Thioinosine / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D014122:Toxoplasma / Q000187:drug effects* / Q000201:enzymology*
D000981:Antiprotozoal Agents; D008024:Ligands; D047428:Protein Kinase Inhibitors; D013868:Thioinosine; D000248:Adenosine Kinase