Sandbox Reserved 829: Difference between revisions

From Proteopedia
Jump to navigationJump to search
No edit summary
No edit summary
Line 71: Line 71:




All recognition helices (also, called helices 3) of Hox factors (such as PDX-1) are able to recognize the TAAT core of the DNA through van der Waals contacts made by Ile 47 with Ade 3 and Thy 4, and through two hydrogen bonds by Asn 51 with Ade 3. Asn 51 also forms a hydrogen bond with Ade 2. Finally, bases Cyt 5*, Thy 6*, and Cyt 7* are recognized through van der Waals contacts with Gln 50 and Met 54. [[http://www.proteopedia.org/wiki/index.php/Image:Nter.jpg ]]   
All recognition helices (also, called helices 3) of Hox factors (such as PDX-1) are able to recognize the TAAT core of the DNA through van der Waals contacts made by Ile 47 with Ade 3 and Thy 4, and through two hydrogen bonds by Asn 51 with Ade 3. Asn 51 also forms a hydrogen bond with Ade 2. Finally, bases Cyt 5*, Thy 6*, and Cyt 7* are recognized through van der Waals contacts with Gln 50 and Met 54. [[http://www.proteopedia.org/wiki/index.php/Image:Nter.jpg ] Part B]   


The N-terminal arm sequence is less well conserved than the recognition helix, but typically includes positively charged Lys or Arg residues. The arm sequence contributes to DNA binding specificity. The N-terminal arm facilitates searching the DNA for binding sites through electro-static attraction by a sliding mechanism or transferring between DNA strands by a ‘‘fly catching’’ mechanism.
The N-terminal arm sequence is less well conserved than the recognition helix, but typically includes positively charged Lys or Arg residues. The arm sequence contributes to DNA binding specificity. The N-terminal arm facilitates searching the DNA for binding sites through electro-static attraction by a sliding mechanism or transferring between DNA strands by a ‘‘fly catching’’ mechanism.