SWI/SNF
In molecular biology, SWI/SNF (SWItch/Sucrose Non-Fermentable), is a subfamily of ATP-dependent chromatin remodeling complexes, which is found in eukaryotes. In other words, it is a group of proteins that associate to remodel the way DNA is packaged. This complex is composed of several proteins – products of the SWI and SNF genes (SWI1, SWI2/SNF2, SWI3, SWI5, SWI6), as well as other polypeptides. It possesses a DNA-stimulated ATPase activity that can destabilize histone-DNA interactions in reconstituted nucleosomes in an ATP-dependent manner, though the exact nature of this structural change is unknown. The SWI/SNF subfamily provides crucial nucleosome rearrangement, which is seen as ejection and/or sliding. The movement of nucleosomes provides easier access to the chromatin, allowing genes to be activated or repressed.
| Snf2 ATPase bound to a nucleosome | |||||||||
|---|---|---|---|---|---|---|---|---|---|
Cryo-EM reconstruction of S. cerevisiae Snf2 ATPase in complex with a nucleosome | |||||||||
| Identifiers | |||||||||
| Symbol | Snf2 | ||||||||
| Pfam | PF00176 | ||||||||
| InterPro | IPR000330 | ||||||||
| SMART | DEXDc | ||||||||
| SCOP2 | 5x0x / SCOPe / SUPFAM | ||||||||
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The human analogs of SWI/SNF are "BRG1- or BRM-associated factors", or BAF (SWI/SNF-A) and "Polybromo-associated BAF", which is also known as PBAF (SWI/SNF-B). There are also Drosophila analogs of SWI/SNF, known as "Brahma Associated Protein", or BAP and "Polybromo-associated BAP", also known as PBAP.