A New Packing Arrangement: Twisted Bundles of Fibers

There are many variations in hemoglobin caused by changes at the amino acid level. A number of DNA base pair changes can have no effect at all, --the same amino acid is produced. But some result in the wrong amino acid being made. Some have a big impact. The sickle cell substitution appears to change the charge in a very sensitive place.

A change in charge on the surface of hemoglobin such as the change in Sickle Cell can make a difference in the way one hemoglobin "packs" with other molecules of hemoglobin.

Hemoglobin changes its shape ever so slightly, and this change allows the inserted amino acid to contact another hemoglobin. This appears to start a chain reaction. It then packs with another hemoglobin into a double fiber, and these in turn join into long solid, twisted fiber sets.

These long twisting strands straighten out the whole cell. The cell membrane itself remains entact but injured, and the whole cell cannot "talk" with other cells using its surface proteins in the usual manner.

Why are people who have sickle cell protected against malaria?

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