X-Message-Number: 14312
From: "John Clark" <>
Subject: Ribosome
Date: Mon, 14 Aug 2000 16:16:12 -0400

In the current issue of Science there is an article by Ban et al that reports 
the 3D atomic

scale structure of the most complex object ever, the largest of the two subunits
of a

ribosome. This thing is huge, 2.6  million daltons,  more than 50 times as big 
as your

average protein. It has 3,000 nucleotides of RNA bent into a complex shape 
folded in

out and around 31 different interlocking proteins. I find this really 
interesting at a lot of

different levels. It's amazing they can find the 3D shape of something this big 
and complex.

The object itself is very important, ribosomes are where proteins are made. 
There are

practical implications, the ribosomes in bacteria are major target for 
There are philosophical implications too.

Two-thirds of the mass of ribosome's comes from RNA, and it turns out that the 

is the catalyst for the protein synthesis, not the one third that is protein as 
you might

expect, the protein acts just as girders to hold the machine together. RNA can 
not only

store information like DNA it can also catalyze chemical reactions like 
proteins. RNA

acting as a enzyme had been noticed before but never at something this important

fundamental to all life. It give support to the theory that when life first 
originated 4 billion
years ago it contained no DNA and no protein, just pure RNA.

           John K Clark    

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