SWISS-MODEL: Modelling protein tertiary and quaternary structure
using evolutionary information.
There are two major categories of proteins with quaternary structure
- fibrous and globular.
Despite this, says Ahnert, the organizing principles that underlie protein quaternary structure
in nature are poorly understood.
The treatment of protein structure in many introductory textbooks, however, is cursory and focuses on the relationships among primary, secondary, tertiary, and quaternary structure
without a clear link to how these levels of organization contribute to functional aspects of the protein.
It is noteworthy that quaternary structure
is essential for CTB function, but this is impossible in some expression systems (9), (11), (15).
This time he focuses upon The School of Athens and the quaternary structure
of Quixote's first part.