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Hot Article: Non-covalent delivery
02 December 2008
In this latest OBC Hot paper, Kevin Burgess (Texas A & M University, US) and colleagues describe non-covalent carriers which have the potential to mediate the transport of proteins into cells. Burgess explains more in this short interview below.
Please explain, for a non-specialist, the significance of your article.
Delivery agents provide an attractive alternative to microinjection techniques because they are not as physically intrusive, and are experimentally simple. The most widely applied delivery agents are TAT-protein fusions, or similar conjugates where oligo-Arg (or similar) residues are covalently attached to proteins. The fact that the attachment is covalent is an important limitation of these systems; it would be more straightforward to simply mix the delivery agent with the protein to be imported (the cargo).
What has motivated you to conduct this work?
Pep-1, a commercially available non-covalent delivery agent, is known to mediate permeation of protein cargos into living cells. However, when the import is done at 37 °C, the cargoes get predominantly trapped into endosomes and only a small amount of protein is delivered free in the cytosol. It is important to be able to deliver the protein intact and freely in the cytosol.
Synthetic non-covalent delivery agent azo-Arg8
Where do you see this work developing in the future?
A milestone was accomplished by discovering that at 4 °C Pep-1, and remarkably, Arg8 (and a synthetic analog, azo-Arg8) faciliate import of labeled proteins into the cytosol. It will be of great interest to be able to import any cargoes inside the cytosol or specific organelles at 37 °C.
Are there any particular challenges facing future research in this area?
We first need to establish the scope and generality of delivery into cells at 4 °C. We also need to monitor the extent to which proteins imported in the cytosol are correctly folded and not proteolytically degraded. Finally, we need to design more efficient non-covalent delivery agents that will allow import of proteins into the cytosol at 37 °C.
Please explain, for a non-specialist, the significance of your article.
Delivery agents provide an attractive alternative to microinjection techniques because they are not as physically intrusive, and are experimentally simple. The most widely applied delivery agents are TAT-protein fusions, or similar conjugates where oligo-Arg (or similar) residues are covalently attached to proteins. The fact that the attachment is covalent is an important limitation of these systems; it would be more straightforward to simply mix the delivery agent with the protein to be imported (the cargo).
What has motivated you to conduct this work?
Pep-1, a commercially available non-covalent delivery agent, is known to mediate permeation of protein cargos into living cells. However, when the import is done at 37 °C, the cargoes get predominantly trapped into endosomes and only a small amount of protein is delivered free in the cytosol. It is important to be able to deliver the protein intact and freely in the cytosol.
Synthetic non-covalent delivery agent azo-Arg8
Where do you see this work developing in the future?
A milestone was accomplished by discovering that at 4 °C Pep-1, and remarkably, Arg8 (and a synthetic analog, azo-Arg8) faciliate import of labeled proteins into the cytosol. It will be of great interest to be able to import any cargoes inside the cytosol or specific organelles at 37 °C.
Are there any particular challenges facing future research in this area?
We first need to establish the scope and generality of delivery into cells at 4 °C. We also need to monitor the extent to which proteins imported in the cytosol are correctly folded and not proteolytically degraded. Finally, we need to design more efficient non-covalent delivery agents that will allow import of proteins into the cytosol at 37 °C.
Link to journal article
Non-covalent delivery of proteins into mammalian cells
Aurore Loudet, Junyan Han, Rola Barhoumi, Jean-Philippe Pellois, Robert C. Burghardt and Kevin Burgess, Org. Biomol. Chem., 2008, 6, 4516
DOI: 10.1039/b809006h
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