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Updated: May 5, 2026
Production of Disulfide-stabilized Transmembrane Peptide Complexes for Structural Studies
Published on: March 6, 2013
Division of labor among monomers within the Mu transposase tetramer
T A Baker1, M Mizuuchi, H Savilahti
1Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health, Bethesda, Maryland 20892.
Abstract:
A single tetramer of Mu transposase (MuA) pairs the recombination sites, cleaves the donor DNA, and joins these ends to a target DNA by strand transfer. Analysis of C-terminal deletion derivatives of MuA reveals that a 30 amino acid region between residues 575 and 605 is critical for these three steps. Although inactive on its own, a deletion protein lacking this region assembles with the wild-type protein. These mixed tetramers carry out donor cleavage but do not promote strand transfer, even when the donor cleavage stage is bypassed. These data suggest that the active center of the transposase is composed of the C-terminus of four MuA monomers; one dimer carries out donor cleavage while all four monomers contribute to strand transfer.
Insights
The Mu transposase (MuA) C-terminus is essential for DNA recombination. A specific 30-amino acid region is critical for DNA cleavage and strand transfer, with all four monomers needed for strand transfer.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Mu transposase (MuA) mediates DNA transposition through a series of steps including DNA cleavage and strand transfer.
- Understanding the functional domains of MuA is crucial for elucidating the mechanism of transposition.
Purpose of the Study:
- To identify the critical regions of Mu transposase (MuA) responsible for DNA cleavage and strand transfer.
- To investigate the role of the C-terminus in the catalytic activity of MuA.
Main Methods:
- Analysis of C-terminal deletion derivatives of MuA.
- Assessing the activity of wild-type and mutant MuA proteins in vitro.
- Formation and analysis of mixed tetramers composed of wild-type and deletion mutant MuA.
Main Results:
- A 30 amino acid region (residues 575-605) in the MuA C-terminus is critical for DNA cleavage and strand transfer.
- Deletion mutants lacking this region are inactive independently but can assemble into mixed tetramers with wild-type MuA.
- Mixed tetramers perform donor DNA cleavage but fail to promote strand transfer.
Conclusions:
- The active center for Mu transposase activity is composed of the C-termini of all four MuA monomers.
- Two monomers are sufficient for donor DNA cleavage, while all four are required for strand transfer.
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