Bacteriophage Mu C protein is a new member of unusual leucine zipper-HTH class of proteins

Chakraborty, Atanu ; Paul, Bindu Diana ; Nagaraja, Valakunja (2007) Bacteriophage Mu C protein is a new member of unusual leucine zipper-HTH class of proteins Protein Engineering Design & Selection, 20 (1). pp. 1-5. ISSN 1741-0126

PDF - Publisher Version

Official URL:

Related URL:


Transcription activator protein C of bacteriophage Mu activates transcription of the late genes, including mom, during the lytic cycle of the phage. C binding to its site leads to the alteration in DNA topology of the promoter elements resulting in RNA polymerase (RNAP) recruitment. At the next step, the transactivator enhances promoter clearance of RNAP from Pmom. The C protein binds DNA with a very high affinity using a carboxylterminal helix turn helix (HTH) motif which has similarity with the HTH from paired domain of Drosophila prd protein. Previous studies established that the protein is dimeric in free and DNA bound forms. We describe now the unique dimerization interface of the protein. Two heptad repeats of hydrophobic amino acids found in the protein were considered to be the candidates for dimerization region. Site-directed mutational analysis revealed that the amino-terminal coiled coil region is not the dimerization determinant. In contrast, similar mutagenesis studies indicated a role for the leucine zipper motif, located in the middle region of the protein, in dimerization. Mixed oligomerization assays confirmed the importance of leucine zipper in C dimer formation establishing the presence of an uncommon zipper-HTH domain in the transactivator.

Item Type:Article
Source:Copyright of this article belongs to Oxford University Press.
Keywords:C Protein; Helix Turn Helix; Leucine Zipper; Phage Mu; Transcription Activation
ID Code:27024
Deposited On:08 Dec 2010 12:50
Last Modified:17 May 2016 10:19

Repository Staff Only: item control page