Table 3

G protein-coupled receptors with four hydroxyl amino acid residues in a acid environment.

Receptor

Species

Sequence

% acidic

Location

Alpha-2C

opossum

  ELEDIELEESSTSE

50

3^rd Loop

Alpha-2A

multiple

         DLEESSSSE

44

3^rd Loop

Dopamine

insect

                    TTTSTPEEPDDE

42

3^rd Loop

Rhodopsin

pig

         DDEASTTTS

33

C terminus

Rhodopsin

arthopod

ESDDVSESASTTTSAEE

33

C terminus

Rhodopsin

vertebrate

       EEDEASTSS

44

C terminus

Rhodopsin

vertebrate

       DEDEESTSS

56

C terminus

Rhodopsin

vertebrate

       DDEEASSSS

44

C terminus

cAMP class E

Dictyostelium

        DEGSSSSSLSSSDEE

33

C terminus

The G Protein-Coupled Receptor Database http://www.gpcr.org/ webcite was searched for four consecutive hydroxyl amino acid residues (either serine or threonine) in a linear sequence that was at least 1/3 acidic (aspartic or glutamic) with no basic residues (lysine or arginine) and which occurred in either the third intracellular loop or the carboxyl-terminal tail.

Deupree et al. BMC Pharmacology 2002 2:9   doi:10.1186/1471-2210-2-9