Python Programming for Biology: Bioinformatics and Beyond

Tertiary  structure:  this  is  how  secondary-structure  elements  of  one  polypeptide

chain come together to form a compact structure. In essence this is the folded, three-

dimensional structure of one protein molecule in isolation.

Quaternary  structure:  this  is  the  structure  that  results  when  multiple  proteins

and/or proteins and other molecules (RNA, DNA, small molecules) come together to

form a larger composite structure that is commonly termed a complex. Some protein

complexes  consist  of  multiple  copies  of  the  same  kind  of  protein  coming  together,

often in a highly symmetric way.

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