Rowland, S.J., Boocock, M.R., MacPherson, A.L., Mouw, K.W., Rice, P.A. and Stark, M.S. (2009) Regulatory mutations in Sin recombinase support a structure-based model of the synaptosome. Molecular Microbiology, 74(2), pp. 282-298. (doi: 10.1111/j.1365-2958.2009.06756.x)
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Publisher's URL: http://dx.doi.org/10.1111/j.1365-2958.2009.06756.x
Abstract
The resolvase Sin regulates DNA strand exchange by assembling an elaborate interwound synaptosome containing catalytic and regulatory Sin tetramers, and an architectural DNA bending protein. The crystal structure of the regulatory tetramer was recently solved, providing new insights into the structural basis for regulation. Here we describe the selection and characterization of two classes of Sin mutations that respectively bypass or disrupt the functions of the regulatory tetramer. Activating mutations, which allow the catalytic tetramer to assemble and function independently at site I (the crossover site), were found at ~20% of residues in the N-terminal domain. The most strongly activating mutation (Q115R) stabilized a catalytically active synaptic tetramer <i>in vitro</i>. The positions of these mutations suggest that they act by destabilizing the conformation of the ground-state site I-bound dimers, or by stabilizing the altered conformation of the active catalytic tetramer. Mutations that block activation by the regulatory tetramer mapped to just two residues, F52 and R54, supporting a functional role for a previously reported crystallographic dimer-dimer interface. We suggest how F52/R54 contacts between regulatory and catalytic subunits might promote assembly of the active catalytic tetramer within the synaptosome.
Item Type: | Articles |
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Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Boocock, Dr Martin and Rowland, Dr Sally-Jane and Stark, Professor Marshall |
Authors: | Rowland, S.J., Boocock, M.R., MacPherson, A.L., Mouw, K.W., Rice, P.A., and Stark, M.S. |
Subjects: | Q Science > QH Natural history > QH345 Biochemistry |
College/School: | College of Medical Veterinary and Life Sciences > School of Molecular Biosciences |
Journal Name: | Molecular Microbiology |
ISSN: | 0950-382X |
ISSN (Online): | 1365-2958 |
Published Online: | 08 June 2009 |
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