Open AccessCyclic nucleotide binding to cAMP receptor protein from Escherichia coli
Author(s) -
DONOSOPARDO Josefa L.,
TURNER Peter C.,
KING Rodney W.
Publication year - 1987
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1987.tb13470.x
Subject(s) - moiety , chemistry , escherichia coli , stereochemistry , protonation , nucleotide , camp receptor protein , ribose , dissociation constant , adenosine , dissociation (chemistry) , residue (chemistry) , receptor , biochemistry , enzyme , organic chemistry , ion , gene expression , promoter , gene
cAMP receptor protein from Escherichia coli has been purified on a large scale. Analogues of cAMP modified on the 6‐NH 2 group of the adenosine ring, the ribose 2′OH group or the cyclic phosphate are able to displace cAMP from its binding site with dissociation constants of similar magnitude to that of cAMP. More extensive modification produces weaker binding. Ultraviolet/visible difference spectroscopy and fluorescence spectroscopy show that the environment of the bound adenosine moiety is considerably less polar than that in aqueous solvent, while an anthraniloyl group substituted on the 2′OH position remains accessible to solvent. The 2‐NH 2 group of cGMP appears to be protonated in the bound form, while no change in the charge state of cAMP is apparent.