Professor Jane Grasby, Department of Chemistry, University of Sheffield
Wednesday 4th June, 1.00 p.m., Stacey Lecture Theatre 1
Flap endonuclease-1 (FEN1), the essential 5’-nuclease of lagging strand DNA replication and repair, is the prototypical member of a superfamily of 5’-nucleases. Superfamily activities span all major nucleic acid metabolic pathways. FEN1 removes displaced 5’-single-stranded RNA or DNA flaps by a single incision one nucleotide into double-stranded DNA, always on the 5’-strand. Combined structural and biochemical(1,2) analyses reveal this specificity is the result of a novel double nucleotide unpairing mechanism, likely shared throughout the superfamily. DNU allows ends of duplexes, and particular DNA strands, to be recognised and targeted for reaction. Recent data (3) suggest that DNU is a function of FEN1 action, rather then a passive fraying of duplex ends. Control of the DNU apparatus, by alternation of protein structure, offers a mechanism to achieve substrate specificity and biological regulation across the superfamily.
1. Human Flap Endonuclease Structures, DNA Double Base Flipping and a Unified Understanding of the FEN1 Superfamily
Susan E. Tsutakawa, Scott Classen, Brian R. Chapados, Andy Arvai, L. David Finger, Grant Guenther, Christopher G Tomlinson, Peter Thompson, Altaf H. Sarker, Binghui Shen, Priscilla K. Cooper, Jane A. Grasby, and John A. Tainer (2011) Cell, 145, 198–211
2. Observation of unpaired substrate DNA in the flap endonuclease-1 active site L. David Finger, Nikesh Patel, Amanda Beddows, Long Ma, Jack C. Exell, Emma Jardine, Anita C. Jones, Jane A. Grasby (2013) Nucleic Acids Research, 41, 9839-9847
3. Proline Scanning Mutagenesis Reveals a Role for the Flap Endonuclease-1 Helical Cap in Substrate Unpairing
Nikesh Patel, Jack C. Exell, Emma Jardine, Ben Ombler, L. David Finger, Barbara Ciani, Jane A Grasby (2013) J. Biol. Chem,. 288, 34239-34248