thermostabilised beta1-adrenoceptor with rationally designed inverse agonist 7-methylcyanopindolol boundthermostabilised beta1-adrenoceptor with rationally designed inverse agonist 7-methylcyanopindolol bound

Structural highlights

5a8e is a 1 chain structure with sequence from Meleagris gallopavo. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.4Å
Ligands:, , ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

ADRB1_MELGA Beta-adrenergic receptors mediate the catecholamine-induced activation of adenylate cyclase through the action of G proteins. This receptor binds epinephrine and norepinephrine with approximately equal affinity.

Publication Abstract from PubMed

Comparisons between structures of the lower case beta1-adrenergic receptor (beta1AR) bound to either agonists, partial agonists or weak partial agonists led to the proposal that rotamer changes of Ser5.46, coupled to a contraction of the binding pocket, are sufficient to increase the probability of receptor activation. Cyanopindolol is a weak partial agonist of beta1AR and, based on the hypothesis above, we predicted that the addition of a methyl group to form 7-methylcyanopindolol would reduce dramatically its efficacy. An eight-step synthesis of 7-methylcyanopindolol was developed and its pharmacology analysed. 7-Methylcyanopindolol bound with similar affinity to cyanopindolol to both beta1AR and beta2AR. As predicted, the efficacy of 7-methylcyanopindolol was dramatically reduced compared to cyanopindolol, acting as a very weak partial of turkey beta1AR and an inverse agonist of human beta2AR. The structure of 7-methylcyanopindolol-bound beta1AR was determined to 2.4 A resolution and found to be virtually identical to the structure of cyanopindolol-bound beta1AR. The major differences in the orthosteric binding pocket are that it has expanded by 0.3 A in 7-methylcyanopoindol-bound beta1AR and the hydroxyl group of Ser5.46 is positioned 0.8 A further from the ligand with respect to the position of the Ser5.46 side chain in cyanopindolol-bound beta1AR. Thus the molecular basis for the reduction in efficacy of 7-methylcyanopindolol compared to cyanopindolol may be regarded as the opposite of the mechanism proposed for the increase in efficacy of agonists compared to antagonists.

Pharmacological Analysis and Structure Determination of 7-Methylcyanopindolol-Bound beta1-Adrenergic Receptor.,Sato T, Baker J, Warne T, Brown G, Leslie A, Congreve M, Tate C Mol Pharmacol. 2015 Sep 18. pii: mol.115.101030. PMID:26385885[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Sato T, Baker J, Warne T, Brown G, Leslie A, Congreve M, Tate C. Pharmacological Analysis and Structure Determination of 7-Methylcyanopindolol-Bound beta1-Adrenergic Receptor. Mol Pharmacol. 2015 Sep 18. pii: mol.115.101030. PMID:26385885 doi:http://dx.doi.org/10.1124/mol.115.101030

5a8e, resolution 2.40Å

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