| 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 | ||||||||
| SCOP | 2eze | ||||||||
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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]
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]