The proposal deals with: 1. RecA and Rad51 interactions with DNA, 2. ATP-F1 synthase, and 3. Polarized-light spectroscopy for structural study of bio-macromolecules. -- Purpose is mechanistic understanding of how DNA recombination is performed by the two types of recombinase, in particular about the roles of DNA stretch, of ATP and metal ion cofactors, and how energy is relocalized to separate non-homologous DNA strands. Polarized-light spectroscopy combined with aromatic residue substitution is used: ´Site Specific Linear Dichroism by Molecular Replacement´ (SSLD-MR), assisted by molecular modelling, contributing structural and mechanistic details. The complex systems will be studied at conditions mimicking key steps of the DNA recombination reaction. Also model systems are studied: we have found that membranes and certain polymer gels catalyse strand exchange via ´hydrophobic catalysis´ which may apply also to the interior of recombinases. -- The ATP-F1 synthase is highly homologous with RecA and Rad51 recombinases. All three systems involve ADP/ATP-related mechanical energy transductions in their respective catalytic functions, the mechanisms of which will be targets for our study. Various intramolecular coupled mechanisms and ´ratchet´ effects are being investigated. -- Third subproject is further development of SSLD-MR for studying complex bio-molecular systems, including also membrane proteins in bilayer membranes and intrinsically disordered protein aggregates.
Full Professor at Physical Chemistry
Funding Chalmers participation during 2012–2014