molecular structures

Have you ever wondered how to view and annotate molecular structures? At least digital versions? It's surprisingly easy and lots of fun. Here's a movie I made that demonstrates how you can use Cn3D, a free structure-viewing program from the NCBI. Luckily, Cn3D behaves almost the same way on both Windows and Mac OS X. ... Read more

If you look below the fold, you can see two molecules locked in a tight embrace. These molecules or their closely related cousins can be found in any cell because their ability to evolve is slowed by their need to interact with each other in the right way. In an earlier post, I asked: Who are they? One partner is a small bit of ... Read more

Last week I posted an image with two molecules (below the fold), one protein and one nucleic acid, and asked you about the probability of finding similar molecules in different species. You gave me some interesting answers. DAG made me clarify my question by asking what I meant by "similarity." I was wondering whether I would be likely to find a statistically relevant match by doing a BLAST search and I hadn't really thought about the cutoff values. I decided to guess and say that that the protein would be about 30% similar and the nucleic acid about 60 ... Read more

This is a fun puzzle. The pink molecule is a protein and the other molecule is a nucleic acid. If I gave you the amino acid sequence of this protein, or the nucleotide sequence of this nucleic acid, what is the probability of finding a similar sequence in a different species (picked at random)? A. High B. Medium C. Low D. It ... Read more

The grocery store magazine covers all say that home made gifts are big this year. So I thought, some of you might like to channel your inner Martha Stewart and make gifts with a science theme. I'm here to help to you make a merry mug with one of our favorite molecules. Yep, we're talking caffeine. 1. First, we'll go to ... Read more

This structure is called a "kissing loop" and I find that name just a bit odd, given the source of the structure.
Now, here's the puzzle: Why would I say that the name "kissing loop" is ironic? Read more

Biology as a second-language: the immersion method Language teachers say the best way to learn a language is by total immersion and even better, spending time in the country where it's spoken conversing with native speakers. See it, hear it, speak it, use it! Put yourself in a position where you must do these four things to survive (or at least find the restroom) and you will learn more rapidly than by any other method. Graduate school serves a similar purpose for scientists. You go from an environment where your fellow ... Read more

Two protein structures from an avian influenza virus are shown below. One form of the protein makes influenza virus resistant to Oseltamivir (Tamiflu®) Don't worry, these proteins aren't from H5N1, but they do come from a related influenza virus that also infects birds.

One protein structure is from a strain that is sensitive to an anti-viral drug called "Tamiflu®". The other structure is from the same virus, except there's a slight difference. A single base change in the viral RNA changed the codon that tells the translation ... Read more

Here's a lovely DNA structure from our friend, human immunodeficiency virus I. I especially like the way that two heart-like shapes appear in the structure.

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Is nature ironic or what? Read more

Last Friday, we had another in the series of weird DNA structures. (You can see the first here). I asked the audience to identify the unusual feature in this molecule. Here's the first picture:

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Here's the answer: ... Read more