[Show abstract][Hide abstract] ABSTRACT: Indole-3-acetyl-L-aspartic acid (IAA-Asp) is a natural product in many plant species and plays many important roles in auxin
metabolism and plant physiology. IAA-Asp hydrolysis activity is, therefore, believed to affect plant physiology through changes
in IAA metabolism in plants. We applied a newly discovered technique, arginine-rich intracellular delivery (AID), to deliver
a bacterial IAA-Asp hydrolase into cells of mung bean (Vigna radiata) seeds and measured its effects on mung bean seed germination. IAA-Asp hydrolase inhibited seed germination about 12 h after
the enzyme was delivered into cells of mung bean seeds both covalently and noncovalently. Mung bean seed germination was delayed
by 36 h when the enzyme protein was noncovalently attached to the AID peptide and longer than 60 h when the enzyme protein
was covalently attached to the AID peptide. Root elongation of mung bean plants was inhibited as much as 90% or 80%, respectively,
when the IAA-Asp hydrolase was delivered with the AID peptide by covalent or noncovalent association. Further thin-layer chromatography
analysis of plant extracts indicated that the levels of IAA increased about 12 h after treatment and reached their peak at
24 h. This result suggests that IAA-Asp hydrolase may increase IAA levels and inhibit seed germination of mung bean plants
and that the AID peptide is a new, rapid, and efficient experimental tool to study the in vivo activity of enzymes of interest in plant cells.
[Show abstract][Hide abstract] ABSTRACT: Plasma membranes of plant or animal cells are generally impermeable to peptides or proteins. Many basic peptides have previously been investigated and covalently cross-linked with cargoes for cellular internalization. In the current study, we demonstrate that arginine-rich intracellular delivery (AID) peptides are able to deliver fluorescent proteins or beta-galactosidase enzyme into animal and plant cells, as well as animal tissue. Cellular internalization and transdermal delivery of protein could be mediated by effective and nontoxic AID peptides in a neither fusion protein nor conjugation fashion. Therefore, noncovalent AID peptides may provide a useful strategy to have active proteins function in living cells and tissues in vivo.
Preview · Article · Sep 2006 · Biochemical and Biophysical Research Communications