HindIII

HindIII restriction endonuclease
Crystallographic structure of the HindIII restriction endonuclease dimer (cyan and green) complexed with double helical DNA (brown) based on the PDB: 2E52​ coordinates.
Identifiers
Symbol	RE_Hindiii
Pfam	PF09518
InterPro	IPR019043
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

HindIII (pronounced "Hin D Three") is a type II site-specific deoxyribonuclease restriction enzyme isolated from Haemophilus influenzae that cleaves the DNA palindromic sequence AAGCTT in the presence of the cofactor Mg²⁺ via hydrolysis.^[1]

The cleavage of this sequence between the AA's results in 5' overhangs on the DNA called sticky ends:

5'-A |A G C T T-3'

3'-T T C G A| A-5'

Restriction endonucleases are used as defense mechanisms in prokaryotic organisms in the restriction modification system. Their primary function is to protect the host genome against invasion by foreign DNA, primarily bacteriophage DNA. There is also evidence that suggests the restriction enzymes may act alongside modification enzymes as selfish elements, or may be involved in genetic recombination and transposition.^[2]