RT Journal Article
SR Electronic
T1 β<sub>1</sub>-Selective Agonist (−)-1-(3,4-Dimethoxyphenetylamino)-3-(3,4-dihydroxy)-2-propanol [(−)-RO363] Differentially Interacts with Key Amino Acids Responsible for β<sub>1</sub>-Selective Binding in Resting and Active States
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 51
OP 58
DO 10.1124/jpet.301.1.51
VO 301
IS 1
A1 Yoshiyuki Sugimoto
A1 Reiko Fujisawa
A1 Ryuji Tanimura
A1 Anne Laure Lattion
A1 Susanna Cotecchia
A1 Gozoh Tsujimoto
A1 Taku Nagao
A1 Hitoshi Kurose
YR 2002
UL http://jpet.aspetjournals.org/content/301/1/51.abstract
AB (−)-1-(3,4-Dimethoxyphenetylamino)-3-(3,4-dihydroxy)-2-propanol [(−)-RO363] is a highly selective β1-adrenergic receptor (β1AR) agonist. To study the binding site of β1-selective agonist, chimeric β1/β2ARs and Ala-substituted β1ARs were constructed. Several key residues of β1AR [Leu110 and Thr117 in transmembrane domain (TMD) 2], and Phe359 in TMD 7] were found to be responsible for β1-selective binding of (−)-RO363, as determined by competitive binding. Based on these results, we built a three-dimensional model of the binding domain for (−)-RO363. The model indicated that TMD 2 and TMD 7 of β1AR form a binding pocket; the methoxyphenyl group ofN-substituent of (−)-RO363 seems to locate within the cavity surrounded by Leu110, Thr117, and Phe359. The amino acids Leu110 and Phe359 interact with the phenyl ring of (−)-RO363, whereas Thr117 forms hydrogen bond with the methoxy group of (−)-RO363. To examine the interaction of these residues with β1AR in an active state, each of the amino acids was changed to Ala in a constitutively active (CA)-β1AR mutant. The degree of decrease in the affinity of CA-β1AR for (−)-RO363 was essentially the same as that of wild-type β1AR when mutated at Leu110 and Thr117. However, the affinity was decreased in Ala-substituted mutant of Phe359 compared with that of wild-type β1AR. These results indicated that Leu110 and Thr117 are necessary for the initial binding of (−)-RO363 with β1-selectivity, and interaction of Phe359 with the N-substituent of (−)-RO363 in an active state is stronger than in the resting state. The American Society for Pharmacology and Experimental Therapeutics