Paulings Pleated Sheets

Linus Pauling- a figure to be respected.  Two Nobel prizes, one in Chemistry, the other the Peace prize.  He developed the concept of electronegativity and used X-Ray Crystallography to to research crystal and protein structures, including the Alpha Helix and the Beta Pleated Sheet.  Yeah- a real bigwig in the history of science.  (Want to know more?  Click here.)

My Microbiology teacher (Dr. B.) had the gall to CHALLENGE Pauling on the structure of Beta Pleated Sheets.  Here's how he told it:  Dr. B was in a lab with a group who were studying secondary protein structures. At some point, someone placed their spiral bound notebook on the overhead projector, which was on.  The spiral binding (structured like an Alpha Helix) threw a shadow up which resembled the observable pattern of the (then theoretical) Beta Pleated Sheet.  "Ah ha!" thought Dr. B, "there is no Beta Pleated Sheet after all- it is only a projection of an Alpha Helix."  Pauling came in to work with the group, and Dr. B. (he hides his face in shame as he recounts the story) argued with Pauling over the structure.  Needless to say, Dr. B. was proven incorrect, and Chemistry and Microbiology students the world over now learn both structures. 

Here's a picture of primary through quaternary protein structures from a Wikipedia article for those who are less familiar with the shapes: