Specific photoaffinity labeling of two plasma membrane polypeptides with an azido auxin
- Oregon State Univ., Corvallis (USA)
Plasma membrane vesicles were isolated from zucchini (Cucurbita pepo) hypocotyl tissue by aqueous phase partitioning and assessed for homogeneity by the use of membrane-specific enzyme assays. The highly pure plasma membrane vesicles maintained a pH differential across the membrane and accumulated a tritiated azido analogue of 3-indoleacetic acid (IAA), 5-azido-(7-{sup 3}H)IAA(({sup 3}H)N{sub 3}IAA), in a manner similar to the accumulation of ({sup 3}H)IAA. The association of the ({sup 3}H)N{sub 3}IAA with membrane vesicles was saturable and subject to competition by IAA and auxin analogues. Auxin-binding proteins were photoaffinity labeled by addition of ({sup 3}H)N{sub 3}IAA to plasma membrane vesicles prior to exposure to UV light and detected by subsequent NaDodSO{sub 4}/PAGE and fluorography. When the reaction temperature was lowered to {minus}196{degree}C, high-specific-activity labeling of a 40-kDa and a 42-kDa polypeptide was observed. Collectively, these results suggest that the radiolabeled polypeptides are auxin receptors. The covalent nature of the label should facilitate purification and further characterization of the receptors.
- OSTI ID:
- 5264213
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America; (USA), Vol. 86:13; ISSN 0027-8424
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AUXINS
RECEPTORS
MEMBRANE PROTEINS
MOLECULAR STRUCTURE
BIOCHEMICAL REACTION KINETICS
CELL MEMBRANES
ELECTROPHORESIS
FAR ULTRAVIOLET RADIATION
MEMBRANES
POLYPEPTIDES
PROTEINS
SEEDS
TRITIUM COMPOUNDS
CELL CONSTITUENTS
ELECTROMAGNETIC RADIATION
HYDROGEN COMPOUNDS
KINETICS
ORGANIC COMPOUNDS
PEPTIDES
PLANT GROWTH REGULATORS
RADIATIONS
REACTION KINETICS
ULTRAVIOLET RADIATION
550201* - Biochemistry- Tracer Techniques