How did a mechanical engineer How did a mechanical engineer come to work on DNA?come to work on DNA?

1981 -1981 - Chris posts a list on his Peterhouse Chris posts a list on his Peterhouse

wall, under the portrait of baby Maxwell:wall, under the portrait of baby Maxwell:

• (a) think about “shells”

• (b) help Rachel with mathematics

• (c) see Aaron about DNA!

1982 1982 - - apply the principle of “bistability” from apply the principle of “bistability” from engineering and early flagella work to DNA helical engineering and early flagella work to DNA helical forms “B” versus “A”forms “B” versus “A”

19831983 - - replace the imaginary helix axis replace the imaginary helix axis from 1950’s fiber work with something from 1950’s fiber work with something better:better:

1984 1984 - - Euler’s six parameters-three Euler’s six parameters-three translations x, y, z and three rotations xy, translations x, y, z and three rotations xy, yz, xz- at any base pair stepyz, xz- at any base pair step

1985 1985 - - look for sequence periodicities of curved look for sequence periodicities of curved

DNA in the nucleosome core of chromatin - predict a DNA in the nucleosome core of chromatin - predict a

Fourier distribution of “roll angles”Fourier distribution of “roll angles”

19871987- - exactly the same principles apply exactly the same principles apply to the interaction of curved DNA with to the interaction of curved DNA with bacterial repressor proteinsbacterial repressor proteins

1988 1988 – – deduce the three-dimensional deduce the three-dimensional shapes of curved DNA in solution or in shapes of curved DNA in solution or in gels - confirm by electron microscopygels - confirm by electron microscopy

Only four parameters (roll, twist) = 0Only four parameters (roll, twist) = 0oo, 35, 35oo for AA/TT, but 3.3for AA/TT, but 3.3oo, 34, 34oo for other steps, for other steps, explain most of the gel-running dataexplain most of the gel-running data

19921992 - - general theory of DNA motion general theory of DNA motion through gels, invokes both “sieving” and through gels, invokes both “sieving” and “deformation”“deformation”

19961996 - - theory of DNA topology when theory of DNA topology when bound to proteins (with L. Lutter)bound to proteins (with L. Lutter)

20012001 - - theory of protein folding as an theory of protein folding as an alpha-helical barrel (with B. Luisi)alpha-helical barrel (with B. Luisi)

An explosion of genomic sequencing and An explosion of genomic sequencing and other biological data: where are all the other biological data: where are all the engineers?engineers?

In the Blue In the Blue Mountains, west Mountains, west of Sydneyof Sydney

No science labs out here! No science labs out here! (near Gloucester, NSW)(near Gloucester, NSW)