Gene Machine by Venki Ramakrishnan

Author:Venki Ramakrishnan
Language: eng
Format: epub, azw3
Publisher: Basic Books
Published: 2018-11-05T16:00:00+00:00

Brian very quickly identified the outlines of the 30S and its characteristic shape in the map. He then went on to find lots of other double helical regions of RNA. We knew that the RNA in the 30S formed around forty of these helices, although some of them were quite short, unlike the long helix (number 44 or h44) that we’d first seen. RNA helices are A form, which is named after the dehydrated form of DNA that Rosalind Franklin first observed, unlike the more typical B form of normal DNA that she saw when DNA was hydrated. We could easily see the narrow but deep major groove and the wide but shallow minor groove that characterize these A-form helices. Our best maps were at around 5.5 Å resolution, which meant we could even see phosphate groups as a series of bumps along a ridge as we followed the helical turn of RNA. Our strategy was working beyond our expectations.

At this point, my colleague Daniela Rhodes suggested that we should report our results in Nature. Daniela is well known for her work on chromatin, but she was also the person who over two decades earlier had done important work on tRNA with Aaron Klug and Brian Clark. We had become good friends during my sabbatical, and she had been strongly supportive of my move to Cambridge. She told an editor at Nature about our results, and he got in touch to say he was very interested in publishing them. We thought a short report describing our progress would be a good way of staking our turf. These short reports in Nature are called letters, for historical reasons, as opposed to articles, which are longer and more substantial papers. But longer is not always better or more important. One of the most famous papers in Nature, the Watson and Crick description of the double helical structure of DNA, is an amazingly short letter of only about eight hundred words.

But something seemed wrong with our maps. We could see a lot of RNA in them, but there seemed to be no sign of proteins. They had to be there since there were about twenty of them in the 30S subunit. Maybe because they are not as dense as the RNA, they weren’t showing up in our maps. I was puzzling over this when I noticed that some of the density looked like tubes that were a lot thinner than the RNA double helices. In fact, they seemed the right size to be the alpha helices that proteins often form, and in a few places the tubes packed against each other in the way that these helices do in proteins. I wrote to Brian and told him what I’d seen and went to bed.

I was not prepared for the surprise that awaited me when I went in to work the next morning. Of course, I had expected the usual emails from Utah telling me what had gone on while I was sleeping, but that morning there were several emails from Brian.

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