HTH - The helix-turn-helix motif is a common prokaryotic...

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The helix-turn-helix motif is a common prokaryotic DNA-binding element. The HTH motif consists of an ~20 amino acid polypeptide that forms two short helices and a turn. The N-terminal helix is a “bracing” helix. The C-terminal helix is the “recognition helix”. Both make contact with DNA. The recognition helix interacts with the major groove. (Usually, two adjacent helices are contacted by dimeric proteins. Replacement of recognition helix residues may alter binding specificity. “Helix swap” experiments only work in special cases. The recognition helix may project into the major groove at various angles. The proteins with HTH motif usually make additional contacts to DNA. The HTH recognition helix has multiple backbone interactions. The HTH structure and function depend on the rest of the protein. The HTH motifs are evolutionarily related and homologous.
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Organization of the central 20 amino-acid HTH “core” 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 434 repressor Q
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This note was uploaded on 02/17/2012 for the course CHEM 212 taught by Professor Staff during the Fall '10 term at Rutgers.

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HTH - The helix-turn-helix motif is a common prokaryotic...

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