John Hopfield: On the surface of the ten-thousand atom molecule, there is a slight change. A small
group of a few atoms on the edge of the molecule is replaced by another small group
of atoms. That's all that happens - an exchange of a few atoms. Yet it's enough
to make people very ill. The effect of the change is to create a sticky point between
on abnormal molecule and its neighbor, causing molecules to pile up on each other.
Normal red cells shaped like discs can easily pass through the small blood vessels
of the body. When hemoglobin molecules stick together, the red cells that carry them
get distorted so badly that they have difficulty getting through the narrow passageways.
Parts of the body are deprived of precious oxygen.
There are thousands upon thousands of ways that two molecules might bind. And for
the moment, the complete mechanical and structural story of sickling remains a mystery.
But knowing where the problem begins, where the first change occurs on the molecule,
can be of help in finding a chemical method for reversing the process and helping
to cure the first known molecular disease.