Type II restriction endonucleases recognise specific DNA sequences and cleave the DNA at fixed positions in or adjacent to these sequences. The recognition sites are often palindromic sequences 4–8 bp long, though some are asymmetric. Most of the enzymes that recognise palindromes are homodimers that interact symmetrically with the recognition site, so that the active site in one subunit is positioned to cleave one strand of the DNA and likewise the second active site on the other strand. The SgrAI endonuclease usually cleaves DNA with two recognition sites more rapidly than DNA with one site, often converting the former directly to the products cut at both sites. In this respect, SgrAI acts like the tetrameric restriction enzymes that bind two copies of their target sites before cleaving both sites concertedly. Here you can see a Wharol-like representation of the structure of SgrAI enzyme in complex with a synthetic target DNA and determined by cryoEM (PDB code: 7SS5)
#molecularart ... #immolecular ... #popart ... #restriction ... #enzyme ... #DNA ... #SgrAI ... #complex ... #cryoem
Structure of the restriction enzyme rendered with @proteinimaging and composed with @corelphotopaint
#molecularart ... #immolecular ... #popart ... #restriction ... #enzyme ... #DNA ... #SgrAI ... #complex ... #cryoem
Structure of the restriction enzyme rendered with @proteinimaging and composed with @corelphotopaint
