Case No. 127 · the exotic forty · have you seen this molecule?

Methyl-coenzyme M reductase

the methane maker, with a nickel heart and six strange amino acids

File sealed

The detectives are still writing this one up. The poster and the facts are below; the film and the interrogation room open soon.

Booking photographs

Methyl-coenzyme M reductase, front view, against a height chart in nanometers — FRONT

Methyl-coenzyme M reductase, side view — SIDE · PDB 1MRO

The suspect, from its real atomic coordinates. Drag to turn it. Height chart in nanometers, a line every 2 nm. Its nickel hearts are buried out of sight. A methane molecule is about a thirtieth as wide.

Rap sheet

Answers to: MCR. Works for archaea only.
Height: 12.7 nm, standing on end.
Weight: 460 zeptograms
Heart: Two F430s, the only known nickel tetrapyrroles in life.
Marks: Six doctored amino acids. One swaps a backbone oxygen for sulfur: thioglycine.
Habits: Frees a methyl radical, which leaves as methane.
Weakness: 3-Nitrooxypropanol in cow feed oxidizes its nickel. 30% less methane.
Record: Its mugshot shows five oddities. A sixth turned up 19 years later.
Last seen: In a cow’s rumen. Run in reverse in Black Sea microbial mats.

120,000,000,000,000,000,000

methane molecules it makes inside one cow every second, give or take.
Cows vary. You’ve never seen one.

CASE FILE: Ermler, U. et al. (1997) Crystal Structure of Methyl-Coenzyme M Reductase: The Key Enzyme of Biological Methane Formation. Science 278, 1457–1462.

The poster on the street

The wanted poster for Methyl-coenzyme M reductase

This is the photocopied wanted poster for Methyl-coenzyme M reductase, No. 127 of the exotic forty. They were made for noticeboards around Boston, Cambridge and the rest of the east coast.

Found one? Scan its QR code with your phone. If you're a signed-in player, the sighting goes on your record with +1 XP.

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