PHIL 2015 Lecture Notes - Lecture 30: Glucose Transporter, Gaba Receptor, Disulfide

• School: York University
• Department: Philosophy
• Course: PHIL 2015
• Professor: Stefan Kipfer

Document Summary

2. 2) describe how these channels can discriminate between anions and cations and between ions of different sizes. Gaba: has narrow pore -> ions too big can"t fit through narrow pore -> not selected, vestibule area: excess positive charged residues on both extracellular and cytoplasmic ends of m2 helix (lysine and arginine) -> attracts anions (ex. Nicotinic ach: m2 helix ends have excess negative charged residues: aspartate and glutamate -> one residue from each of the 5 chains -> forms ring of negative charge on external surface -> repels anions (ex. Cl-) and attracts cations (na+, k+): ring of negative charges found on both extracellular and cytoplasmic pore surface. 2. 3) use a kinetic scheme to describe what is known about the relation between receptor occupancy and gating. General: 2 binding sites available -> increasing ligand -> does not increase response; increase receptor = more gating action and frequency of receptor opening, opening/closing -> microseconds -> between a2r and a2r*.