Residues 377-389 from the delta subunit of Torpedo californica acetylcholine receptor are located in the cytoplasmic surface.
Torpedo californica acetylcholine receptor (AcChR) enriched, sealed vesicles have been specifically labeled on the cytoplasmic surface with pyridoxal 5'-phosphate (Perez-Ramirez, B., and Martinez-Carrion, M., 1989, Biochemistry 28, 5034-5040). After chromatography of the peptide fragments produced by trypin digestion of labeled AcChR, several fractions containing the phosphopyridoxyl label were obtained. Edman degradation identified one of the fractions, with sequence SRSELMFEKQSER, as corresponding to residues 377-389 in the delta subunit (primary structure). The latter must be a cytoplasmic region of this transmembranous protein, and residue delta K385 must reside in a water-soluble exposed domain of the cytosolic side of the membrane. Introduction of phosphopyridoxyl residues allows for their potential use as probes of conformational changes in the cytosolic surface of the receptor molecule.
Division of Cell Biology and Biphysics, School of Biological Sciences, University of Missouri-Kansas City, Missouri 64110.
B
B
Perez-Ramirez
A
A
Iriarte
M
M
Martinez-Carrion
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism* / Q000648:ultrastructure; D002851:Chromatography, High Pressure Liquid; D007700:Kinetics; D046911:Macromolecular Substances; D008961:Models, Structural; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis*; D017433:Protein Structure, Secondary; D011732:Pyridoxal Phosphate / Q000378:metabolism; D011978:Receptors, Nicotinic / Q000737:chemistry* / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D014101:Torpedo; D014357:Trypsin
D046911:Macromolecular Substances; D010446:Peptide Fragments; D011978:Receptors, Nicotinic; D011732:Pyridoxal Phosphate; D014357:Trypsin