Ranjan, Amitabh and Sharma, S. and Banerjee, R. and Sen, U. and Sen, Ranjan (2013) Structural and mechanistic basis of anti-termination of Rho-dependent transcription termination by bacteriophage P4 capsid protein Psu. Nucleic Acids Research, 41 (14). pp. 6839-6856. ISSN 0305-1048

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Abstract

The conserved bacterial transcription terminator, Rho, is a potent target for bactericidal agents. Psu, a bacteriophage P4 capsid protein, is capable of inducing anti-termination to the Rho-dependent transcription termination. Knowledge of structural and mechanistic basis of this anti-termination is required to design peptide-inhibitor(s) of Rho from Psu. Using suppressor genetics, cross-linking, protein foot-printing and FRET analyses, we describe a conserved disordered structure, encompassing 139-153 amino acids of Rho, as the primary docking site for Psu. Also a neighbouring helical structure, comprising 347-354 amino acids, lining its central channel, plays a supportive role in the Rho-Psu complex formation. Based on the crystal structure of Psu, its conformation in the capsid of the P4 phage, and its interacting regions on Rho, we build an energy-minimized structural model of the Rho:Psu complex. In this model, a V-shaped dimer of Psu interacts with the two diagonally opposite subunits of a hexameric Rho, enabling Psu to form a 'lid' on the central channel of the latter. We show that this configuration of Psu makes the central channel of Rho inaccessible, and it causes a mechanical impediment to its translocase activity.

Item Type:	Article
Depositing User:	Users 2 not found.
Date Deposited:	15 Sep 2015 08:58
Last Modified:	24 Nov 2015 19:41
URI:	http://cdfd.sciencecentral.in/id/eprint/519

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