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J Med Chem. 2012 May 24;55(10):4847-60. doi: 10.1021/jm300396n. Epub 2012 May 16.

Structure-guided design of A(3) adenosine receptor-selective nucleosides: combination of 2-arylethynyl and bicyclo[3.1.0]hexane substitutions.

Author information

1
Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States.

Abstract

(N)-Methanocarba adenosine 5'-methyluronamides containing known A(3) AR (adenosine receptor)-enhancing modifications, i.e., 2-(arylethynyl)adenine and N(6)-methyl or N(6)-(3-substituted-benzyl), were nanomolar full agonists of human (h) A(3)AR and highly selective (K(i) ∼0.6 nM, N(6)-methyl 2-(halophenylethynyl) analogues 13 and 14). Combined 2-arylethynyl-N(6)-3-chlorobenzyl substitutions preserved A(3)AR affinity/selectivity in the (N)-methanocarba series (e.g., 3,4-difluoro full agonist MRS5698 31, K(i) 3 nM, human and mouse A(3)) better than that for ribosides. Polyaromatic 2-ethynyl N(6)-3-chlorobenzyl analogues, such as potent linearly extended 2-p-biphenylethynyl MRS5679 34 (K(i) hA(3) 3.1 nM; A(1), A(2A), inactive) and fluorescent 1-pyrene adduct MRS5704 35 (K(i) hA(3) 68.3 nM), were conformationally rigid; receptor docking identified a large, mainly hydrophobic binding region. The vicinity of receptor-bound C2 groups was probed by homology modeling based on recent X-ray structure of an agonist-bound A(2A)AR, with a predicted helical rearrangement requiring an agonist-specific outward displacement of TM2 resembling opsin. Thus, the X-ray structure of related A(2A)AR is useful in guiding the design of new A(3)AR agonists.

PMID:
22559880
PMCID:
PMC3371665
DOI:
10.1021/jm300396n
[Indexed for MEDLINE]
Free PMC Article

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