I Wish I'd Made You Angry Earlier

Yesterday was Max Perutz's 101st birthday. Perutz won the Nobel in 1962 for his work in x-ray crystallography. I recently found a collection of essays he'd written (I Wish I'd Made You Angry Earlier: Essays on Science, Scientists, and Humanity and given the family history (both of my husband's parents were crystallographers of some note) picked it up to read.

The title essay is about Perutz's graduate research, where he and a colleague come close to unlocking the secret of the α-helix. Two things struck me in this essay. First was the origin of the terms α-helix and β-sheet. Bill Astbury, a crystallographer working with the Wool Research Associate in England had taken two crystal structures of a sample of kertain. The first diffraction experiment (the α sample) showed a simple and characteristic diffraction pattern, the β experiment, done after heating and stretching the sample gave a different pattern. Astbury concluded that the first pattern must arise from a coiled structure, the second from straight strands of amino acids laid out in a repeating pattern. Thus, theubiquitous α-helix and β sheet.

Perutz and Kendrew tried to crack the problem of figuring out just how the amino acids wound into the coil by building a model using a broomstick with nails hammered into to indicate the repeat (5.1 A). Even with all the sophisticated computer visualization (literally) at my fingertips, there is something about a tangible model that beats it all, even if I end up resorting (as I have) to using chickenwire. A few years ago, I solved a structural mystery by making a paper-doll like model of the molecule of interest.

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The title? Pauling and Corey solved the mystery of the α-helix before Perutz and Kendrew. Reading the paper so angered and frustrated Perutz that he was able to design and execute the crucial experiment that proved beyond a doubt that Pauling and Corey were correct. Bragg, Pertuz's Ph.D. advisor told him that he'd wished he'd make him angrier earlier!