1dh3: Difference between revisions

[[Image:1dh3.gif|left|200px]]<br /><applet load="1dh3" size="350" color="white" frame="true" align="right" spinBox="true"  

The cAMP responsive element-binding protein (CREB) is central to second messenger regulated transcription. To elucidate the structural mechanisms of DNA binding and selective dimerization of CREB, we determined to 3.0 A resolution, the structure of the CREB bZIP (residues 283-341) bound to a 21-base pair deoxynucleotide that encompasses the canonical 8-base pair somatostatin cAMP response element (SSCRE). The CREB dimer is stabilized in part by ionic interactions from Arg(314) to Glu(319') and Glu(328) to Lys(333') as well as a hydrogen bond network that links the carboxamide side chains of Gln(322')-Asn(321)-Asn(321')-Gln(322). Critical to family selective dimerization are intersubunit hydrogen bonds between basic region residue Tyr(307) and leucine zipper residue Glu(312), which are conserved in all CREB/CREM/ATF-1 family members. Strikingly, the structure reveals a hexahydrated Mg(2+) ion bound in the cavity between the basic region and SSCRE that makes a water-mediated DNA contact. DNA binding studies demonstrate that Mg(2+) ions enhance CREB bZIP:SSCRE binding by more than 25-fold and suggest a possible physiological role for this ion in somatostatin cAMP response element and potentially other CRE-mediated gene expression.

1DH3 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Mus_musculus Mus musculus] with <scene name='pdbligand=MG:'>MG</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DH3 OCA].  

[[Category: Brennan, R G.]]

[[Category: Goodman, R H.]]

[[Category: Schumacher, M A.]]

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