Dataset Information


Regulatory mutations in Sin recombinase support a structure-based model of the synaptosome.

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 approximately 20% of residues in the N-terminal domain. The most strongly activating mutation (Q115R) stabilized a catalytically active synaptic tetramer in vitro. 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.


PROVIDER: S-EPMC2764113 | BioStudies | 2009-01-01


REPOSITORIES: biostudies

Similar Datasets

2008-01-01 | S-EPMC2428073 | BioStudies
2011-01-01 | S-EPMC3238390 | BioStudies
2004-01-01 | S-EPMC1271755 | BioStudies
1981-01-01 | S-EPMC1162963 | BioStudies
1000-01-01 | S-EPMC4227559 | BioStudies
1967-01-01 | S-EPMC1270396 | BioStudies
2018-01-01 | S-EPMC6172260 | BioStudies
2010-01-01 | S-EPMC2976518 | BioStudies
2002-01-01 | S-EPMC6758053 | BioStudies
1985-01-01 | S-EPMC1145152 | BioStudies