Purification of and Properties of the Cyclic Adenosine 3',5'-Monophosphate Receptor Protein which Mediates Cyclic Adenosine 3',5'-Monophosphate-dependent Gene Transcription in Escherichia coli

A procedure is described for the purification of cyclic adenosine 3',5'-monophosphate receptor protein (CRP) from MATERIALS AND METHODS Chemicals-Cyclic AMP, cyclic [3H] AMP (16.3 Ci per mmole), and [5-3H]CTP (17.9 Ci per mmole) were obtained from Schwaw BioResearch.AMP, ATP, GTP, CTP, and UTP were from P-L Biochemicals, while dithiothreitol was from Calbiochem.1 The abbreviations used are: Zac, the lactose operon; gal, the galactose operon; cyclic AMP, cyclic adenosine 3',5'-monophosphate; CRP, cyclic AMP receptor protein; DTNB, 5,5'-dithiobis-(2-nitrobenzoic acid); DTP, 4,4'-dithiodipyridine; cyclic GMP, cyclic guanosine 3',5'-monophosphate. *J.