Oligomeric structure of p21 ras proteins as determined by radiation inactivation

Journal Article · Fri Jul 15 04:00:00 EDT 1988 · J. Biol. Chem.; (United States)

OSTI ID:6908306

Santos, E; Nebreda, A R; Bryan, T; Kempner, E S

Using radiation inactivation we determined that p21 ras proteins exhibit an oligomeric target size when assayed both structurally and functionally. Similar target sizes of p21 in ras-transformed cells and in purified preparations of the protein suggested that its structure is homo-oligomeric. p21 monomers were destroyed by radiation with the same target size as the GTP binding activity, indicating the occurrence of a tight association allowing energy transfer between the monomers. Irradiation in the presence of GTP, dithiothreitol, or EDTA did not change the target size. Normal (Gly12) and transforming (Lys12) forms of the protein exhibited similar target sizes. The homo-oligomeric structure suggests that p21 ras proteins do not conform to the structure of monomeric alpha subunits in classical G proteins (alpha beta gamma heterotrimers) and establishes similarities with other homo-oligomeric proteins (such as Escherichia coli CRP) which acquire the active conformation through subunit reorientation upon nucleotide binding.

• Research Organization: National Institute of Allergy and Infectious Diseases, Bethesda, MD (USA)
• OSTI ID: 6908306
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 263:20; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

560120* -- Radiation Effects on Biochemicals
Cells
& Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMINO ACIDS
ANIMAL CELLS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CARBOXYLIC ACIDS
CHELATING AGENTS
CONNECTIVE TISSUE CELLS
EDTA
ENERGY TRANSFER
FIBROBLASTS
MEMBRANE PROTEINS
MOLECULAR STRUCTURE
MOLECULAR WEIGHT
ORGANIC ACIDS
ORGANIC COMPOUNDS
PROTEINS
RADIATION EFFECTS
SOMATIC CELLS