AT-hook

 The AT-hook is a DNA-binding motif present in many proteins, including the high mobility group (HMG) proteins,^[1] DNA-binding proteins from plants ^[2] and hBRG1 protein, a central ATPase of the human switching/sucrose non-fermenting (SWI/SNF) remodeling complex.^[3]

AT-hook
solution structure of a complex of the second dna binding domain of human hmg-i(y) bound to dna dodecamer containing the prdii site of the interferon-beta promoter, nmr, 35 structures
Identifiers
Symbol	AT_hook
Pfam	PF02178
InterPro	IPR017956
SMART	AT_hook
SCOP2	2eze / SCOPe / SUPFAM
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

The second AT-hook of HMGA1 (black ribbon) bound to the minor-groove of AT-rich DNA. The amino-acid side chains and nucleotides have been hidden.

This motif consists of a conserved, palindromic, core sequence of proline-arginine-glycine-arginine-proline, although some AT-hooks contain only a single proline in the core sequence. AT-hooks also include a variable number of positively charged lysine and arginine residues on either side of the core sequence.^[4] The AT-hook binds to the minor groove of adenine-thymine (AT) rich DNA, hence the AT in the name. The rest of the name derives from a predicted asparagine/aspartate "hook" in the earliest AT-hooks reported in 1990.^[5] In 1997 structural studies using NMR determined that a DNA-bound AT-hook adopted a crescent or hook shape around the minor groove of a target DNA strand (pictured at right).^[6] HMGA proteins contain three AT-hooks, although some proteins contain as many as 30.^[5] The optimal binding sequences for AT-hook proteins are repeats of the form (ATAA)_n or (TATT)_n, although the optimal binding sequences for the core sequence of the AT-hook are AAAT and AATT.^[7]

This article uses material from the Wikipedia article  Metasyntactic variable, which is released under the  Creative Commons Attribution-ShareAlike 3.0 Unported License.