Characterization of promoter recognition complexes formed by CRP and CytR for repression and by CRP and RNA polymerase for activation of transcription on the Escherichia coli deoP2 promoter

TY - JOUR

T1 - Characterization of promoter recognition complexes formed by CRP and CytR for repression and by CRP and RNA polymerase for activation of transcription on the Escherichia coli deoP2 promoter

AU - Møllegaard, N E

AU - Valentin-Hansen, P

AU - Nielsen, Peter E.

PY - 1993/8/15

Y1 - 1993/8/15

N2 - The structure of the cAMP-CRP-CytR repression complex and the cAMP CRP-RNA polymerase initiation complex at the deoP2 promoter of E. coli have been probed by DNase I and uranyl footprinting. In the CRP2-CytR complex all protein DNA-phosphate contacts at CRP-1 and CRP-2 are retained, and in addition two new minor groove contacts, ascribed to phosphate-CytR interactions, are observed at -60 between the CRP sites. The contacts are compatible with a model in which the promoter DNA is wrapped around a complex of two CRPs and one CytR. In the RNA polymerase-CRP complex, the CRP-1 phosphate contacts are almost identical to those seen in the repression complex and strong RNA polymerase contacts are seen in the -10 and in the +10 regions. Most noteworthy are minor groove contacts in the -60 region ascribed to RNA polymerase contacts upstream from the CRP. Furthermore, binding of CRP to the CRP-2 target does not seem to interfere with RNA polymerase binding. Thus, a model is suggested in which the DNA is wrapped around a complex of RNA polymerase and one CRP. Finally, the results show that CytR and RNA polymerase are rivals that compete for binding with CRP at deoP2 and that CytR functions as an antiactivator.

AB - The structure of the cAMP-CRP-CytR repression complex and the cAMP CRP-RNA polymerase initiation complex at the deoP2 promoter of E. coli have been probed by DNase I and uranyl footprinting. In the CRP2-CytR complex all protein DNA-phosphate contacts at CRP-1 and CRP-2 are retained, and in addition two new minor groove contacts, ascribed to phosphate-CytR interactions, are observed at -60 between the CRP sites. The contacts are compatible with a model in which the promoter DNA is wrapped around a complex of two CRPs and one CytR. In the RNA polymerase-CRP complex, the CRP-1 phosphate contacts are almost identical to those seen in the repression complex and strong RNA polymerase contacts are seen in the -10 and in the +10 regions. Most noteworthy are minor groove contacts in the -60 region ascribed to RNA polymerase contacts upstream from the CRP. Furthermore, binding of CRP to the CRP-2 target does not seem to interfere with RNA polymerase binding. Thus, a model is suggested in which the DNA is wrapped around a complex of RNA polymerase and one CRP. Finally, the results show that CytR and RNA polymerase are rivals that compete for binding with CRP at deoP2 and that CytR functions as an antiactivator.

KW - Bacterial Proteins/metabolism

KW - Base Sequence

KW - Carrier Proteins/metabolism

KW - Cyclic AMP/metabolism

KW - Cyclic AMP Receptor Protein

KW - DNA, Bacterial/metabolism

KW - DNA-Directed RNA Polymerases/metabolism

KW - Deoxyribonuclease I

KW - Escherichia coli

KW - Escherichia coli Proteins

KW - Molecular Sequence Data

KW - Promoter Regions, Genetic

KW - Receptors, Cyclic AMP/metabolism

KW - Repressor Proteins/metabolism

KW - Temperature

KW - Transcriptional Activation

M3 - Journal article

C2 - 8394345

SN - 0021-9258

VL - 268

SP - 17471

EP - 17477

JO - The Journal of Biological Chemistry

JF - The Journal of Biological Chemistry

IS - 23

ER -