1. Division of Biology, Indian Institute of Science Education and Research, Pune 411008, India
2. MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
3. DNA-Protein Interactions Unit, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
4. Diamond Light Source, Harwell Science and Innovation Campus, Fermi Avenue, Didcot OX11 0DE, UK