Venki Ramakrishnan

to during stitching together a growing protein chain, you're going to add amino acids to the growing protein chain because amino acids are the building blocks. So that part where it's joined or the part where the genetic code is recognized in the ribosome, those parts are highly conserved. They're even conserved across kingdoms.

to during stitching together a growing protein chain, you're going to add amino acids to the growing protein chain because amino acids are the building blocks. So that part where it's joined or the part where the genetic code is recognized in the ribosome, those parts are highly conserved. They're even conserved across kingdoms.

So there are only very small differences in the so-called peptidyl transfer center, which is where the amino acid bond is formed, peptide bond is formed. There are very subtle differences between, say, bacteria and humans. But overall, the ribosomes of bacteria look very different. For example, the human ribosomes are...

So there are only very small differences in the so-called peptidyl transfer center, which is where the amino acid bond is formed, peptide bond is formed. There are very subtle differences between, say, bacteria and humans. But overall, the ribosomes of bacteria look very different. For example, the human ribosomes are...

almost twice as large, and they've expanded both their RNA and protein components considerably.

almost twice as large, and they've expanded both their RNA and protein components considerably.

Environmental factors, viruses. So I think part of the reason that eukaryotic, that is a translation in higher organisms, with a nucleus is more complicated, is because there's more regulation in higher organisms. And Initially, biologists thought that almost all of the regulation of genes had to do with how much and when you made mRNA from a section of DNA.

Environmental factors, viruses. So I think part of the reason that eukaryotic, that is a translation in higher organisms, with a nucleus is more complicated, is because there's more regulation in higher organisms. And Initially, biologists thought that almost all of the regulation of genes had to do with how much and when you made mRNA from a section of DNA.

And that once the mRNA was made, the ribosome inevitably had to just do its thing, almost like a slave. But that's not how it is. It turns out that control exists both... at the mRNA production level, but also at the protein production level. So what we call translational control. And this means that the cell has ways of deciding when to start making proteins.

And that once the mRNA was made, the ribosome inevitably had to just do its thing, almost like a slave. But that's not how it is. It turns out that control exists both... at the mRNA production level, but also at the protein production level. So what we call translational control. And this means that the cell has ways of deciding when to start making proteins.

or it has ways of detecting when protein synthesis has gone wrong, when ribosomes have stalled because they've run out of amino acids. And what do you do about stalled ribosomes? So there's a whole series of control mechanisms and regulatory mechanisms. And the interesting thing is viruses will often hijack the ribosome. So they will shut down what's called the initiation machinery.

or it has ways of detecting when protein synthesis has gone wrong, when ribosomes have stalled because they've run out of amino acids. And what do you do about stalled ribosomes? So there's a whole series of control mechanisms and regulatory mechanisms. And the interesting thing is viruses will often hijack the ribosome. So they will shut down what's called the initiation machinery.

This is what tells the ribosome where to start on the mRNA. It doesn't start right at the extreme end. It has to start somewhere and then go along until it finds the first ribosome. codon, the first amino acid signal to be made. And that process of initiation is very complex. And what viruses do is they shut down the host initiation. So none of the host genes can be made into protein.

This is what tells the ribosome where to start on the mRNA. It doesn't start right at the extreme end. It has to start somewhere and then go along until it finds the first ribosome. codon, the first amino acid signal to be made. And that process of initiation is very complex. And what viruses do is they shut down the host initiation. So none of the host genes can be made into protein.

And then they have alternative ways of recruiting ribosomes to their own mRNA. And so they effectively hijack all of the ribosomes to make their message. In fact, the first gene product of coronavirus is something called NSP1. What NSP1 does is shuts down initiation from host mRNAs and somehow still allows coronavirus to make its own genes, you know, proteins from its own genes.

And then they have alternative ways of recruiting ribosomes to their own mRNA. And so they effectively hijack all of the ribosomes to make their message. In fact, the first gene product of coronavirus is something called NSP1. What NSP1 does is shuts down initiation from host mRNAs and somehow still allows coronavirus to make its own genes, you know, proteins from its own genes.

So there's a lot of... controlled regulation that's going on. And so even though the structure of the ribosome, the first structures came out from bacteria in about 2000, and then gradually we learned more and more about structure, the field is still going forward in all these complicated directions.

So there's a lot of... controlled regulation that's going on. And so even though the structure of the ribosome, the first structures came out from bacteria in about 2000, and then gradually we learned more and more about structure, the field is still going forward in all these complicated directions.

I don't think so. But as I've mentioned that there is this subset of the ribosome community that believes in specialized ribosomes. And they do have, you know, some data to support their view. So I think that it's still a matter of debate in the community. And it could be that there are specialized ribosomes. I wouldn't be completely surprised.

I don't think so. But as I've mentioned that there is this subset of the ribosome community that believes in specialized ribosomes. And they do have, you know, some data to support their view. So I think that it's still a matter of debate in the community. And it could be that there are specialized ribosomes. I wouldn't be completely surprised.