BIOC 4580 Lecture 15: Channels & Pores
1 Mar 2017
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Document Summary
Today, we continue with the idea of a facilitated transport to discuss bacterial pores and eukaryotic channels, particularly the roles of selectivity and gating. Pores and channels are tm proteins with central hydrophilic passage. Solutes with appropriate size and change can pass rapidly in either direction by diffusion, providing the selectivity filter allows them to do so. Pores and ion channels can be studied by patch-clamp experiments. Gating is the phenomenon of closing the channel for a bried period of time, depending on the local electrochemical potential. The lipid environment is also important for channel function annular lipids form hydrophobic, electrostatic and hydrogen-bonded interactions with proteins, and match membrane width to the protein. Review small molecules can enter the can through a carrier or a pore/channel e. g. valinomycin & gramicidin as small peptidic transporters, glut1 & ae1 (band 3) as tm transporters. Pores e. g. bacterial porins, also in mitochondria & chloroplasts.
