Molecular Recognition of cAMP by an RNA Aptamer
Two classes of RNA aptamers that bind the second messenger adenosine 3‘,5‘-cyclic monophosphate (cAMP; 1) were isolated from a random-sequence pool using in vitro selection. Class I and class II aptamers are formed by 33- and 31-nucleotide RNAs, respectively, and each is comprised of similar stem−lo...
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Published in | Biochemistry (Easton) Vol. 39; no. 30; pp. 8983 - 8992 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
01.08.2000
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Subjects | |
Online Access | Get full text |
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Summary: | Two classes of RNA aptamers that bind the second messenger adenosine 3‘,5‘-cyclic monophosphate (cAMP; 1) were isolated from a random-sequence pool using in vitro selection. Class I and class II aptamers are formed by 33- and 31-nucleotide RNAs, respectively, and each is comprised of similar stem−loop and single-stranded structural elements. Class II aptamers, which dominate the final selected RNA population, require divalent cations for complex formation and display a dissociation constant (K D) for cAMP of ∼10 μM. A representative class II aptamer exhibits substantial discrimination against 5‘- and 3‘-phosphorylated nucleosides such as ATP, 5‘-AMP, and 3‘-AMP. However, components of cAMP such as adenine and adenosine also are bound, indicating that the adenine moiety is the primary positive determinant of ligand binding. Specificity of cAMP binding appears to be established by hydrogen bonding interactions with the adenine base as well as by steric interactions with groups on the ribose moiety. In addition, the aptamer recognizes 8,5‘-O-cycloadenosine (2) but not N 3,5‘-cycloadenosine (3), indicating that this RNA might selectively recognize the anti conformation of the N-glycosidic bond of cAMP. |
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Bibliography: | Funding for this work was provided by NIH (GM59343) and the Yale Diabetes and Endocrinology Research Center (DERC). M.K. was supported by Sankyo Co. LTD of Japan. R.R.B. is the recipient of a Hellman Family Fellowship and a fellowship from the David and Lucile Packard Foundation. ark:/67375/TPS-0HBRV6J6-5 istex:50C7E60FB739DBE1C32A951AA62A90B9BDB8D717 ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0006-2960 1520-4995 |
DOI: | 10.1021/bi000149n |