Lecture 3 - Proteins and Neurons.
What makes neurons special?
- There are more different proteins expressed in the brain then anywhere
- They have special proteins that allow for the speicial abilities. Its their
internal special proteins that make them special.
- Neurofilaments, Neurotubules, allow neurons to create their long processes
and carry transmitters and signals.
- Presynaptic terminals are really complex in terms of protein structure.
- Special properties of axons that allow them to carry AP are Voltage gated
channels and leakage channels. First, ion pumps that seperate ions, and they
move back and forth via voltage gated channels and leakage channels.
- The AP is carried along the surface, where the voltage channels are
embedded to create a membrane potential.
Voltage gates NA channel.
- proposed by Hodking and Huxley in the 1950s.
- A singlele transmembrane protein, a series of alpha helices, through S1 to
S6 that surrond the pore when they wrap around to form a 3D structure.
- lead to the understainding of how proteins fold up and make channels.
How DNA makes proteins.
- DNA and mRNA are easier to characterize.
- Primary protein structure is the initial chain of amino acids, coming out of
-2nday protein structure: 2 cystines create a disulfide bond (each cystine has
a sulfide), allowing the creation of a secondary structure.
- tertiary structure made by weaker bonds, by interactions with other amino
acids. (the final organization of the protein)
- whether they become membrane or cytosolic proteins is determined by
whether the AA's bind to lipids or not.
- hydrophilic: cytosol proteins.
- hydrophobic: membrane proteins. (lipophilic)
- sorting of the proteins:
- voltage gated channels are concentrated in nodes of ranvier
- the end of t