Cyclic AMP-induced conformational change of cyclic AMP receptor protein (CRP): intragenic suppressors of cyclic AMP-independent CRP mutations.
We isolated and characterized crp mutations in Escherichia coli that allow cyclic AMP (cAMP) receptor protein to function without cAMP. These mutants defined a region involved in the cAMP-induced allosteric change of cAMP receptor protein that is necessary for activation of the protein. Currently, we have isolated intragenic suppressors of the crp mutations. These crp (Sup) mutants require cAMP for activity. The crp (Sup) mutations map in regions which define new sites of changes involved in cAMP receptor protein activation. From these results, we suggest that to activate cAMP receptor protein cAMP brings about (i) a hinge reorientation to eject the DNA-binding F alpha-helices, (ii) proper alignment between the two subunits, and (iii) an adjustment between the position of the two domains. Cyclic GMP fails to effect the last step.
Garges
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Developmental Genetics Section, National Cancer Institute, Bethesda, Maryland 20892.
Adhya
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D000495:Allosteric Site; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D011487:Protein Conformation; D011953:Receptors, Cyclic AMP / Q000235:genetics*; D013489:Suppression, Genetic
D004269:DNA, Bacterial; D011953:Receptors, Cyclic AMP; D000242:Cyclic AMP