Space rock contains organic molecular feast (BBC)

By Doreen Walton
Science reporter, BBC News

Scientists say they have confirmed that a meteorite that crashed into earth 40 years ago contains millions of different organic compounds.

It is thought the Murchison meteorite could be even older than the Sun.

"Having this information means you can tell what was happening during the birth of the Solar System," said lead researcher Dr Philippe Schmitt-Kopplin.

The results of the meteorite study are published in the Proceedings of the National Academy of Sciences.
***
A study using high resolution analytical tools including spectroscopy allowed the team to identify 14,000 different compounds including 70 amino acids in a sample of the meteorite.
***
more: http://news.bbc.co.uk/2/hi/science/nature/8516319.stm

Imagine what kind of bizarre life forms there would be if a different set of those 70 amino acids had been used.

If you had different enzymes that transcribed DNA or RNA into some of those other 70 amino acids, they would still fold into proteins of various shapes. Although using different enzymes and proteins would make its chemistry incompatible with ours, life based on those proteins and enzymes would not otherwise be that different.

We don't got numpty genetic bases and sevnty odd amino acids because coding for that many amino acids would result in an unacceptable level of error at the genetic level.

Instead we have 4(5) (C, G, A, T (& U)) genetic bases forming 3 base codons with 64 possible combinations coding for only twenty two amino because the redundancy gives what is mathematically demonstrable as being very close to the optimal compromise between genetic mutability and stability.

I bet you can explore just as much protein shape space with 20 amino acids as you could with 70. For that matter, I bet we don't really need 20. It's just what history left us with.

I wish I was smart and focused enough to be a scientist.

;-)

But more seriously, an interesting addition to the data on abiogenesis, or perhaps even panspermia.

So complex that its a mystery how they could have possibly evolved?

Google for pics of the standard 20 AA chemical structures. Alanine is just a carboxyl group stuck to an amino group, but the others are all some variant of COOH-R-NH3 where R is a short substituent carbon side-chain. Of course, the generic term "amino acid" encompasses LOTS more than the simple twenty of so used by all living organisms on Earth-- any molecule with the correct basic form qualifies, and the R-substituent can be arbitrarily complex-- they just don't occur in earthly life that way. The ones that are incorporated into proteins on Earth are all pretty simple.

not so complex that the simplest ones can't be formed from abiotic precursors.

http://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment

Now there's a nice, horrendously complex dissertation subject that would have no purpose at all.

Unless the purpose would be to make other people scratch their heads.