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Wednesday, June 10, 2009

Monday's Molecule #125: Winner

Only one person guessed the molecule and that person was Bill Chaney from the University of Nebraska. Nebraska is very much like one of the provinces in western Canada so I count him as a honorary Canadian!

Naturally Bill also got the correct Nobel Laureate.

The molecule is lipoarabinomannan, also known as LAM. It's a complex derivative of phosphatidylinositol characterized by the presence of numerous mannose residues and branching arabinose chains. LAM is part of the cell wall of mycobacteria, including Mycobacterium tuberculosis, the bacteria that causes tuberculosis.

LAM is one of the major antigens in tuberculin, a complex that is easily isolated from cultures of M. tuberculosis. The complex antigen was used in skin tests for tuberculosis. Robert Koch was the first scientist to isolate tuberculin and he received the Nobel Prize in 1905 for his contributions to understanding how bacteria cause disease.

This is the tentative structure of a very important molecule. It's "tentative" because the exact structure hasn't been fully worked out and because the "molecule" is heterogeneous—it's actually a mixture of several similar molecules.

Identify this molecule by giving its common name and the organism(s) from which it is derived. This particular molecule is part of a much larger complex that was first identified over 100 years ago. The person who discovered that large complex received a Nobel Prize. Identify the Nobel Laureate.

The first person to identify the molecule and the Nobel Laureate, wins a free lunch at the Faculty Club. Previous winners are ineligible for six weeks from the time they first won the prize. Please note the change in the length of time you are ineligible. The idea is to give more more people a chance to win.

There are nine ineligible candidates for this week's reward: Laura Gerth of the University of Notre Dame, Stefan Tarnawsky of the University of Toronto, Dima Klenchin of the University of Wisconsin, Madison, Adam Santoro of the University of Toronto., Michael Clarkson of Waltham MA (USA), Òscar Reig of Barcelona, Maria Altshuler of the University of Toronto, Mike Fraser of the University of Toronto, and Jaseon Oakley of the University of Toronto.

Mike has saved Canadians from embarrassment.

I still have one extra free lunch donated by a previous winner to a deserving undergraduate so I'm going to continue to award an additional free lunch to the first undergraduate student who can accept it. Please indicate in your email message whether you are an undergraduate and whether you can make it for lunch.


Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) and I'll pick the first email message that correctly identifies the molecule and names the Nobel Laureate(s). Note that I'm not going to repeat Nobel Prizes so you might want to check the list of previous Sandwalk postings by clicking on the link in the theme box.

Correct responses will be posted tomorrow.

Comments will be blocked for 24 hours.

[Image Credit: The structure of Mycobacterium tuberculosis lipoarabinomannan (LAM) by Achim Treumann and Steve Homans.]

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