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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
Summary
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.