TABLE 3.

Sequence alignment between the α_1A-AR and the β₂-AR for aromatic residues in TMs 4 and 5 involved in catecholamine binding and activation. Phenylalanine (F) residues in the α_1A-AR are near the surface of the receptor and not conserved in the β₂-AR. Serine (S) residues in TM5 are bolded for comparison. The numbers refer to the number of amino acids in the primary sequence for each receptor.

183

TM4 α1AAR

W

G

F

L

P

G

I

S

I

V

L

S

L

V

W

V

C

L

L

A

190

β2-AR

H

M

Q

I

P

L

F

S

T

L

G

S

V

I

W

V

M

L

I

V

187

Tm5 α1AAR

G

Y

V

L

F

S

A

L

G

S

F

Y

V

P

L

A

I

I

L

V

M

202

β2-AR

A

Y

A

I

A

S

S

I

V

S

F

Y

V

S

L

V

V

M

V

F

Y