Premium
Structural analysis of purified beta‐adrenergic receptors
Author(s) -
Fraser Claire M.,
Kerlavage Anthony R.,
Mariani Andrew P.,
Venter J. Craig
Publication year - 1987
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.340020105
Subject(s) - receptor , photoaffinity labeling , chemistry , trypsin , gel electrophoresis , peptide , ion chromatography , affinity chromatography , size exclusion chromatography , chromatography , high performance liquid chromatography , biochemistry , enzyme
Abstract We have characterized the structure of purified beta‐adrenergic receptors by a combination of photoaffinity labeling, high performance liquid chromatography (HPLC)‐tryptic mapping, CNBr fragmentation, target size analysis, and electron microscopy of purified receptor molecules. Guinea pig lung beta‐adrenergic receptors purified by affinity chromatography, ion exchange chromatography, and HPLC size exclusion chromatography or photoaffinity labeled with [125] ‐iodocyanopindolol diazirine displayed mobilities on sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) that corresponded to M r = 68,000. Purified, radioiodinated guinea pig lung beta‐receptors were subjected to complete trypsin digestion and subsequent reverse‐phase HPLC analysis, which revealed nine peptides. Active site labeling and tryptic digestion of partially purified hamster lung beta‐receptors produced one peptide, whereas CNBr digestion of the same material produced two labeled fragments, yielding information about the location of the active site within the primary sequence. Purified guinea pig lung receptors were examined with transmission electron microscopy. Electron micrographs revealed slightly asymmetric, rod‐shaped structures with an average length of 13 nm and width of 3.4 nm. Many receptors were arranged as apparent dimeric structures. These findings confirm data obtained from target size analysis of guinea pig lung beta‐receptors in situ which suggest that receptors may exist as oligomeric arrays in the native membrane. Taken together, these data provide information about putative functional domains of the beta‐adrenergic receptor and its quaternary structure.