•Substitutions:
Alanine generally prefers to substitute with other small amino acid, Pro, Gly, Ser.
•Role in structure: Alanine is arguably the most boring amino acid. It is not particularly hydrophobic and is
non-polar. However, it contains a normal
C-beta carbon, meaning that it is
generally as hindered as other amino acids with
respect to the conforomations that the backbone can adopt. For this reason, it is not surprising to see Alanine present in just about all non-critical protein contexts.
•Role in function: The Alanine side chain is very non-reactive, and is thus rarely directly involved in
protein function. However it can play a role
in substrate recognition or
specificity, particularly in interactions with other non-reactive atoms such as carbon.