3D reconstruction of the Mu transposase and the Type 1 transpososome: a structural framework for Mu DNA transposition
Open Access
- 17 March 2005
- journal article
- Published by Cold Spring Harbor Laboratory in Genes & Development
- Vol. 19 (7) , 840-852
- https://doi.org/10.1101/gad.1291405
Abstract
Mu DNA transposition proceeds through a series of higher-order nucleoprotein complexes called transpososomes. The structural core of the transpososome is a tetramer of the transposase, Mu A, bound to the two transposon ends. High-resolution structural analysis of the intact transposase and the transpososome has not been successful to date. Here we report the structure of Mu A at 16-Å and the Type 1 transpososome at 34-Å resolution, by 3D reconstruction of images obtained by scanning transmission electron microscopy (STEM) at cryo-temperatures. Electron spectroscopic imaging (ESI) of the DNA-phosphorus was performed in conjunction with the structural investigation to derive the path of the DNA through the transpososome and to define the DNA-binding surface in the transposase. Our model of the transpososome fits well with the accumulated biochemical literature for this intricate transposition system, and lays a structural foundation for biochemical function, including catalysis in trans and the complex circuit of macromolecular interactions underlying Mu DNA transposition.Keywords
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