Tertiary and quaternary structure of lung beta-adrenergic receptors
Guinea pig lung beta/sub 2/-adrenergic receptors (..beta..AR)specifically labeled with a photoaffinity probe, (/sup 125/I)-iodocyanopindolol diazirine, have a molecular mass (M/sub r/) of 68 kDa on SDS-PAGE. When labeled ..beta..AR are subjected to limited proteolysis in the membrane, water soluble fragments of M/sub r/ = 43, 30, 27 and 25 kDA are produced. These data indicate that over 50 percent of the ..beta..AR protrudes from the membrane into the extracellular space. Purification of ..beta..AR by sequential chromatography on alprenolol-Sepharose, DEAE-Sepharose and size exclusion HPLC indicates that the ..beta..AR is extracted from membranes as an oligomeric complex. Two peaks of ..beta..AR that correspond to apparent molecular weights of 370,000 (t=36 min) and 170,000 (t=43 min) elute from HPLC columns. Radioiodination of these fractions and analysis by SDS-PAGE indicates that peak 36 contains ..beta..AR (68 kDa) purified to homogeneity; peak 43 contains ..beta..AR plus other proteins. If ..beta..AR from DEAE columns are allowed to stand at 4/sup 0/C for 7 days prior to HPLC purification, all ..beta..AR elute in peak 43. These data suggest that ..beta..AR are isolated from membranes as dissociable oligomeric complexes. Target size analysis (TSA) of intact ..beta..AR in situ supports the idea of ..beta..AR oligomers. Application of TSA to ..beta..AR indicates that the ..beta..AR has a functional molecular size of 124,000 daltons in the membrane and 270,000 daltons when solubilized with digitonin.
- Research Organization:
- National Institutes of Health, Bethesda, MD
- OSTI ID:
- 5253491
- Report Number(s):
- CONF-8606151-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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RECEPTORS
MOLECULAR STRUCTURE
PURIFICATION
SYMPATHOMIMETICS
AFFINITY
CELL MEMBRANES
EXTRACELLULAR SPACE
GUINEA PIGS
IODINE 125
LIQUID COLUMN CHROMATOGRAPHY
LUNGS
MOLECULAR WEIGHT
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CHROMATOGRAPHY
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
RESPIRATORY SYSTEM
RODENTS
SEPARATION PROCESSES
SPACE
VERTEBRATES
550201* - Biochemistry- Tracer Techniques