Article thumbnail

The role of the T-loop of the signal transducing protein PII from Escherichia coli

By Rene Jaggi, Wendy Ybarlucea, Eong Cheah, Paul D. Carr, Karen J. Edwards, David L. Ollis and Subhash G. Vasudevan


AbstractThe 3D structure of PII, the central protein that controls the level of transcription and the enzymatic activity of glutamine synthetase in enteric bacteria revealed that residues 37–55 form the ‘T’ loop, part of which protrudes from the core of the protein. Within this loop are the only two tyrosine residues that occur in the polypeptide, and one of them, Tyr-51, has been shown by chemical modification studies to be the site of uridylylation. Since tyrosine at position 46 is conserved in all known PII, proteins, oligonucleotide directed mutagenesis was used to investigate the role of the two residues. Changing Tyr-51 to phenylalanine or serine abolished uridylylation. Altering tyrosine at position 46 to phenylalanine affected the rate of uridylylation of the protein. This latter mutation does not alter the structure of PII but the reduction in the uridylylation efficiency suggests a role for this residue in recognition and binding of the sensor enzyme uridylyl transferase

Publisher: Published by Elsevier B.V.
Year: 1996
DOI identifier: 10.1016/0014-5793(96)00737-5
OAI identifier:
Download PDF:
Sorry, we are unable to provide the full text but you may find it at the following location(s):
  • (external link)
  • https://s3-eu-west-1.amazonaws... (external link)
  • Suggested articles

    To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.