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Probing the binding site of the A1 adenosine receptor reengineered for orthogonal recognition by tailored nucleosides

Title
Probing the binding site of the A1 adenosine receptor reengineered for orthogonal recognition by tailored nucleosides
Authors
Palaniappan K.K.Gao Z.-G.Ivanov A.A.Greaves R.Adachi H.Besada P.Hea O.K.Ae Y.K.Seung A.C.Lak S.J.Jacobson K.A.
Ewha Authors
정낙신
Issue Date
2007
Journal Title
Biochemistry
ISSN
0006-2960JCR Link
Citation
vol. 46, no. 25, pp. 7437 - 7448
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
His272 (7.43) in the seventh transmembrane domain (TM7) of the human A 3 adenosine receptor (AR) interacts with the 3′ position of nucleosides, based on selective affinity enhancement at a H272E mutant A 3 AR (neoceptor) of 3′-ureido, but not 3′-OH, adenosine analogues. Here, mutation of the analogous H278 of the human A1 AR to Ala, Asp, Glu, or Leu enhanced the affinity of novel 2′- and 3′-ureido adenosine analogues, such as 10 (N6-cyclopentyl- 3′-ureido-3′-deoxyadenosine), by > 100-fold, while decreasing the affinity or potency of adenosine and other 3′-OH adenosine analogues. His278 mutant receptors produced a similar enhancement regardless of the charge character of the substituted residue, implicating steric rather than electrostatic factors in the gain of function, a hypothesis supported by rhodopsin-based molecular modeling. It was also demonstrated that this interaction was orientationally specific; i.e., mutations at the neighboring Thr277 did not enhance the affinity for a series of 2′- and 3′-ureido nucleosides. Additionally, H-bonding groups placed on substituents at the N6 or 5′ position demonstrated no enhancement in the mutant receptors. These reengineered human A1 ARs revealed orthogonality similar to that of the A3 but not the A 2A AR, in which mutation of the corresponding residue, His278, to Asp did not enhance nucleoside affinity. Functionally, the H278D A1 AR was detectable only in a measure of membrane potential and not in calcium mobilization. This neoceptor approach should be useful for the validation of molecular modeling and the dissection of promiscuous GPCR signaling. © 2007 American Chemical Society.
DOI
10.1021/bi7001828
Appears in Collections:
약학대학 > 약학과 > Journal papers
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