1. Automated determination of interhelical angles for protein alpha helices from coordinate data Robert Fraser, James Stewart, Janice Glasgow Queen's University School of Computing, Kingston, ON

2. Protein Structure Contact Maps Helix Packing Models Proposed Method Results

3. The HUGE picture Sequence  Structure Structure  Function I’m working on a tiny bit of the first step

4. Protein Structure Different levels of structure We’re interested in alpha helices Used with permission from Petsko, G.A. and D. Ringe, Protein Structure and Function, 2004

5. Contact Maps Distance map represents full 3D structure Contact map is a binary version 10Ǻ threshold used here

6. Knobs and Holes Steric surface of the molecule

7. Two surfaces to a helix

8. Sign is important

9. Angle method if (d a × d b ) · (b 0 – a 0 ) > 0 then the top vector is rotated clockwise else the top vector is rotated counter-clockwise Clockwise  negative sign

10. Comparison to observed values

11. Results 4.1° +/- 3.2° of observed data 3.6° +/- 1.9° after removing an outlier

12. Acknowledgements Kelly Fraser Janice Glasgow James Stewart Henk Meijer Mehdi Hedjazi Alan Ableson Eduardo Zuviria Tony Kuo

13. Thank you Questions?