Characterization of a crp* mutant of the E. coli cAMP receptor protein
One of the crp* mutants previously isolated to activate lac promoter in vivo has been characterized with regard to its biochemical properties. CRP*592 shows a more open conformation than CRP as indicated by its sensitivity to proteolytic attack. Dithionitrobenzoic acid mediated intersubunit crosslinking of CRP requires cAMP; this reaction occurs with unliganded CRP*592. Binding of CRP to its site on the lac promoter and activation of abortive initiation is effected by cAMP but not by cGMP. CRP*592 can activate abortive initiation in the presence of cAMP or cGMP and also at a high CRP*592 concentration in the absence of cyclic nucleotide. DNase I footprinting shows that cAMP-CRP* binds to its site on lac P/sup +/ while unliganded CRP* and cGMP-CRP* form a stable complex with the (/sup 32/P)lac P/sup +/ only in the presence of RNA polymerase. While cGMP binds to CRP it cannot replace cAMP in effecting the conformation necessary for site specific promoter binding; the weakly active unliganded CRP*592 can be shifted to a functional conformation by cAMP, cGMP and RNA polymerase.
- Research Organization:
- Hunter College of City Univ. of New York, NY
- OSTI ID:
- 6074765
- Report Number(s):
- CONF-870644-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 46:6; ISSN FEPRA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
AMP
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CHEMICAL PROPERTIES
DAYS LIVING RADIOISOTOPES
ENZYMES
ESCHERICHIA COLI
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
MEMBRANE PROTEINS
MICROORGANISMS
MUTANTS
NUCLEI
NUCLEOTIDES
NUCLEOTIDYLTRANSFERASES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
POLYMERASES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
RNA POLYMERASES
TRACER TECHNIQUES
TRANSFERASES