Alpha hemolysin is one of the very few protein structures that’s not only breathtakingly pretty and intricate but which is also the epicenter of a true technological breakthrough.
The entire structure resembles a flower and traverses a membrane. Beta sheets run along each other to form a 14-strand beta barrel ‘stem’ while other beta sheets line up next to each other at the rim to form the ‘petals’. Both these substructures enclose a remarkable, 100 A long solvent-filled channel. And most impressively, all these subunits self-assemble.
The practical reason why alpha hemolysin is so fascinating is because it is the linchpin of next generation DNA sequencing technology. By utilizing the solvent-filled channel as a nanopore, researchers are threading DNA strands through it and sequencing individual nucleotide bases by looking at minute changes in electrical current across the pore. The technology has already been commercialized and promises to reduce both the cost and time of sequencing.
Alpha hemolysin is thus one of the most perfect examples of combining elegant form with breakthrough technological function. It’s as good an example as I know of nature’s unsurpassed ability to create both beauty and utility in one fell swoop. —Ashutosh Jogalekar