Editing Protein tertiary structure (section)

=== Ligand binding ===
The structure of a protein, such as an [[enzyme]], may change upon binding of its natural ligands, for example a [[Cofactor (biochemistry)|cofactor]]. In this case, the structure of the protein bound to the ligand is known as holo structure,  while the unbound protein has an apo structure.<ref>{{cite journal|pmid=20066034|pmc=2796265|year=2010|last1=Seeliger|first1=D|title=Conformational transitions upon ligand binding: Holo-structure prediction from apo conformations|journal=PLOS Computational Biology|volume=6|issue=1|page=e1000634|last2=De Groot|first2=B. L.|doi=10.1371/journal.pcbi.1000634|bibcode=2010PLSCB...6E0634S |doi-access=free }}</ref>

Structure stabilized by the formation of weak bonds between amino acid side chains
- Determined by the folding of the polypeptide chain on itself (nonpolar residues are located
inside the protein, while polar residues are mainly located outside)
- Envelopment of the protein brings the protein closer and relates a-to located in distant regions of the sequence
- Acquisition of the tertiary structure leads to the formation of pockets and sites suitable for the recognition and
the binding of specific molecules (biospecificity).