Double sided RNA

Ouch! Big error here. The nomenclature of these guys is a bit of a mess, and I tripped myself up. First, then, let me correct myself. The base, let's stick with adeninine as our example, is, after having a pentose sugar attached, referred to as a nucleoside. Here it would be adenosine. The nucleoside can be mon- di- or tri-phosphorylated, then it is a phosporylated nucleoside, here adenosine 5'-monophospahte etc. The phosphorylated nucleoside is referred to as a nucleotide. Sorry about that.
But now, to further confuse the issue, historically adensosine 5'-monophosphate (AMP) was referred to as adenylic acid or adenylate. Fortunately these terms are not musch used now except in the naming of the enzymes which synthesise or act on them and when referring to polymeric structures. Here's a fairly modern example. You may have heard about mRNA having a poly(A) tail. That symbol stands for polyadenylic acid, and the process whereby this is added to mRNA is called polyadenylation.
And finally. When the ribo- and deoxyribonucleoside triphosphates are incorporated into RNA and DNA, they retain the first 5'-phosphate group. Remembering that AMP, for example, was called adenylic acid, you can see why RNA and DNA are acids.
Phew. Was that needed?
 
invert_nexus said:
Alright. That makes sense. So. The difference here and between the D and L isomers is the fact that we're dealing with all oxygens then, right? This enables them to swap electrons in a way that the carboxyl, amino, hydrogen, and R side chain of the amino acid can't?

Is this true of all similar bonds? Or does it require a negatively charged atom? It probably does, right? Because there need to be an excess of electrons.

Oh. And while I'm at it. Why is it that it's only the L isomer found in most lifeforms? (I seem to remember it saying some deep sea creatures use D.) I'm forgetting right now (it's late) but the L form is used in proteins whereas the D from is used in... nucleotides? Or... something else. I'm blanking. Right? But why does it differentiate like this? Any particular reason or is it just one of those weird arbitrary things about cellular functioning?

Edit:
Sugars. Nearly all sugars are D isomers while amino acids are L.
Why?
Click to expand...

Kind of. The fact that they're all the same atom (and thus all have the same electronegativity) means they're able to equally share these electrons, hence enabling resonance. But remember that in order to get chirality (the whole mirror image thing), remember that you need to have four distinct groups on the central carbon.

I'm not sure why amino acids are predominantly of the L-form; it's probably just one of those quirks of evolution. I've also never heard of deep sea creatures using D-isomers, but I do know that certain bacteria have evolved enzymes that create D-isomers of amino acids in an attempt to evade the immune system, which has proved quite successful for them.
 
Getting back to the original subject of dsRNA, the hot area of microRNAs has just become a whole lot hotter. The June issue of Nature (Volume 435 Number 7043) has a number of very interesting papers indicating that aberrant miRNA expression (and the subsequent altered regulation of genes) is involved in the development of a variety of different cancers.

Here is a science news story for the layman....

Cancer experts in a spin over tiny RNA<P>

Here is the News and Views summary from Nature....

Cancer genomics: Small RNAs with big impacts

"Although they are tiny, microRNAs can have large-scale effects because they regulate a variety of genes. These minuscule molecules are now definitively linked to the development of cancer."<P>
 
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