BIO 361 Lecture Notes - Lecture 16: Peptide, Hemoglobin
10 Jul 2016
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Document Summary
The c-termini of each polypeptide chain are heavily involved in the formation of ion pairs or salt bridges. These alpha-beta salt bridges, are dependent on the quaternary conformation of the protein whether or not oxygen has been bound to the protein. The intra-beta chain salt bridges and the 4 inter-alpha salt bridges are dependent on whether oxygen is bound to the polypeptide chain. Therefore, 6 of 8 salt bridges are associated with specific binding of oxygen to each chain. 4 of the 8 are associated with residues that undergo pk changes when oxygen is bound. These salt bridges have amino acids that undergo pk changes and are sources of bohr protons. Each time an oxygen binds to a polypeptide chain, one salt bridge associated with a bohr proton is broken. When protein undergoes quaternary conformational change, there are breakages of salt bridges and 2,3. The term salt bridge is shorthand for oxygenation linked salt bridges.
