The Pf3 coat protein contacts TM1 and TM3 of YidC during membrane biogenesis

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Christian Klenner1, Jijun Yuan, Ross E Dalbey

  • 1Institute of Microbiology and Molecular Biology, University of Hohenheim, 70599 Stuttgart, Germany.

FEBS Letters
|November 11, 2008
PubMed

Insights

Bacteriophage Pf3 coat protein inserts into E. coli membranes via YidC insertase. Disulfide cross-linking revealed Pf3 coat protein interacts with YidC's first and third transmembrane segments during biogenesis.

Area of Science:

  • Membrane Biology
  • Protein Biogenesis
  • Bacteriophage Biology

Background:

  • The YidC insertase facilitates the membrane insertion of specific proteins, including the bacteriophage Pf3 coat protein.
  • Understanding the precise interactions between YidC and its substrates is crucial for elucidating membrane protein biogenesis pathways.

Purpose of the Study:

  • To determine which transmembrane segments of the YidC insertase interact with the Pf3 coat protein during its membrane insertion.
  • To map the specific contact points between YidC and Pf3 coat protein within the membrane.

Main Methods:

  • Utilized a disulfide cross-linking strategy to probe in vivo interactions.
  • Engineered single cysteine mutations in each transmembrane region of YidC.
  • Introduced a cysteine mutation at the center of the Pf3 coat protein's hydrophobic region.

Main Results:

  • Cross-linking confirmed that the Pf3 coat protein interacts with the first and third transmembrane segments (TM1 and TM3) of YidC.
  • Detailed disulfide mapping indicated that a specific face of TM3 of YidC directly contacts the Pf3 coat protein.

Conclusions:

  • The YidC insertase engages the Pf3 coat protein through its transmembrane segments during membrane insertion.
  • TM1 and TM3 of YidC are key interaction sites for the Pf3 coat protein, with TM3 showing a specific face-mediated contact.

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