The Origin of Cellular Life

26-06-2015

Department of Bionanoscience

Today there was a very special guest speaker at TU Delft: Nobel Prize winner Jack Szostak came to talk about his research on ‘the Origin of Cellular Life’. He started with one of the core questions he and his team are trying to answer:

“Is it Easy or Hard to make life?”

Or slightly differently formulated:

“Is life really that complicated or does it just seem that way because it has been evolving for more than 3.5 billion years?”

When you think about it, it is a very hard question to answer. We only know the concept of cells, life’s basic building blocks, for roughly 300 years.

Today it is generally accepted that the genetic information of organisms is written in the DNA code. This code reproduces itself (and thereby makes mistakes) for its offspring and it transcribes itself into a slightly different code of RNA. This RNA then translates to proteins that are the real functional elements. But who said this Central Dogma, as we know it today, is 3.5 billion years old? Szostack explained to us the theory that in early life, DNA and proteins weren’t present as a vital part for organisms. Maybe these organisms’ genome consisted just of RNA. RNA can be seen as an intermediate between DNA and protein, having both the chemical structure for code encryption like DNA, and also the ability to be to fold into a functional molecule just like proteins do.

However, there are still some problems with RNA as molecular motor behind life. RNA is much less stable and also single-stranded. Also, non-enzymatic RNA replication, which theoretically could be possible, is too slow and inaccurate. A third but not last problem is that the A:U bonding in RNA has only two hydrogen bonds, where the A:T bonding in DNA has three. Thereby the structure of RNA is much more sensitive to wobble-formation and also less stable.

While (nano) biologists, chemists, physicists and the rest of the scientific world will struggle for quite some time with the questions mentioned above, it is fascinating to see how far we already are. It is in my opinion one of the most intriguing fields of research within our curriculum, and to have it being explained by a Nobel Prize winner made this lecture extra special.

 

Kasper Spoelstra

wkspoelstra@hotmail.nl

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