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Prolyl isomerization as a molecular timer in phage infection

Barbara Eckert1, Andreas Martin, Jochen Balbach

  • 1Laboratorium für Biochemie und Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, D-95440 Bayreuth, Germany.

Nature Structural & Molecular Biology
|June 7, 2005
PubMed

Insights

A proline residue acts as a molecular timer in filamentous phage fd infection, controlling infectivity by regulating the slow cis-trans isomerization of a peptide bond. This rate can be tuned by mutations, impacting phage activation.

Area of Science:

  • Molecular Biology
  • Virology
  • Biochemistry

Background:

  • Prolyl cis-trans isomerization is a slow reaction crucial for protein folding.
  • Filamentous phage fd infects Escherichia coli cells via its gene-3-protein.

Purpose of the Study:

  • Investigate the role of proline isomerization in phage fd infection.
  • Determine how proline acts as a molecular timer for phage activation.

Main Methods:

  • Analysis of gene-3-protein structure and function.
  • Site-directed mutagenesis to alter the proline residue and surrounding sequence.
  • Assessing phage infectivity rates.

Main Results:

  • Proline 213 (Pro213) in the gene-3-protein acts as a molecular timer.
  • The cis-trans isomerization of the Gln212-Pro213 peptide bond controls phage infectivity.
  • Mutagenesis can alter the switching rate and thus the phage's infective state.

Conclusions:

  • Proline isomerization is a key regulatory mechanism in phage fd infection.
  • The phage utilizes a slow isomerization event as a timer for activation.
  • The local sequence around Pro213 fine-tunes the phage's infectivity through isomerization rates.

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