Antibodies to a peptide from the maize auxin-binding protein have auxin agonist activity.
The major auxin-binding protein in maize membranes is thought to function as a physiological receptor. From earlier information, including the use of site-directed irreversible inhibitors, several of the amino acids likely to form part of the active auxin-binding site were provisionally assigned. Inspection of the amino acid sequence of the auxin-binding protein showed a short region containing all but one of these amino acids. We find that antisera raised against a synthetic peptide encompassing this region recognize all isoforms of the maize auxin-binding protein together with homologous polypeptides in other species. We further find that the antibodies hyperpolarize protoplast transmembrane potential in an auxin-like manner. We conclude that these antibodies display auxin agonist activity and that we have identified an essential portion of the auxin-binding site.
Venis
M A
MA
Horticulture Research International, East Malling, Kent, United Kingdom.
Napier
R M
RM
Barbier-Brygoo
H
H
Maurel
C
C
Perrot-Rechenmann
C
C
Guern
J
J
D000595:Amino Acid Sequence; D000906:Antibodies; D007210:Indoleacetic Acids / Q000378:metabolism*; D007425:Intracellular Membranes / Q000187:drug effects / Q000502:physiology; D008565:Membrane Proteins / Q000302:isolation & purification; D008861:Microsomes / Q000187:drug effects / Q000502:physiology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D010937:Plant Growth Regulators; D018521:Plant Physiological Phenomena; D010940:Plant Proteins; D011523:Protoplasts / Q000502:physiology; D011956:Receptors, Cell Surface / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D003313:Zea mays / Q000502:physiology*
D000906:Antibodies; D007210:Indoleacetic Acids; D008565:Membrane Proteins; D009280:Naphthaleneacetic Acids; D010455:Peptides; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011956:Receptors, Cell Surface; C046131:auxin receptor, plant; C034182:1-naphthaleneacetic acid