Sunday, February 22, 2009

To this day, no one knows what they do.

From Metamodern:

"What’s in the Vault?

by Eric Drexler on February 22, 2009

A vault structure, about 40 x 76 nm in size.
Vault structure
(a single protein in red)

“The Structure of Rat Liver Vault
at 3.5 Angstrom Resolution”
H Tanaka et al., Science,
323: 384–388 (2009).

They’re called “vaults”. They‘re in our cells, and in those of every plant, animal, and fungus. Like ribosomes, they’re atomically precise self-assembled structures made of protein and RNA, but they’re big and hollow, large enough to pack many ribosomes inside. They’re relatively simple and symmetric: A vault consists of two identical halves, each consisting almost entirely of 39 identical copies of a single, large protein (see figure). The vault structure was recently determined to near-atomic resolution, revealing enough detail to show how the proteins fold and fit together. Looking forward, this information could help protein engineers develop methodologies for designing large self-assembling structures.

Vaults are unusual in many ways, but what I find most surprising about them is this:

To this day, no one knows what they do."

Me:

Don the libertarian Democrat 02.22.09 at 4:49 pm UTC

Does anyone know what they did? Are they vestigial?

And a reply:

Eric Drexler 02.22.09 at 9:26 pm UTC

@ Don — A mutation or two would be enough to halt vault production, so they must have an ongoing function in cells, yet to quote from the recent Science paper, “the cellular function remains unclear”. From what I’ve read elsewhere, studying them wasn’t fashionable until relatively recently, with the discovery of a nebulous link to the resistance of some cancer cells to cytotoxic drugs.

@ Michael — A recent afterword (though under a different label) is in Engines 2.0, an e-book linked near the top of this page at E-drexler.com. I’ve been intending to write something similar and post it with the html version.

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