molecular structures
sporte | November 3, 2008Want to learn more about Parkinson's disease? See why a single nucleotide mutation messes up the function of a protein?
I have a short activity that uses Cn3D (a molecular viewing program from the NCBI) to look at a protein that seems to be involved in a rare form of Parkinson's disease and I could sure use beta testers.
If you'd like to do this, I need you to follow the directions below and afterwards, go to a web form and answer a few questions. Don't worry about getting the wrong answers. I won't know who you are, so I won't know if you answered anything wrong.
If you have any concerns…
sporte | September 25, 2008Lots of bloggers in the DNA network have been busy these past few days writing about Google's co-founder Sergey Brin, his blog, his wife's company (23andme), and his mutation in the LRRK2 gene.
I was a little surprised to see that while other bloggers (here, here, here, and here) have been arguing about whether or not the mutation really increases the risk to the degree (20-80%) mentioned by Brin, no one has really looked into the structure and biochemistry of the LRRK2 protein to see if there's a biochemical explanation for Parkinson's risk. I guess that task is up to me.
Let's begin at…
sporte | August 21, 2008One of the things that drives me crazy on occasion is nomenclature. Well, maybe not just nomenclature, it's really the continual changes in the nomenclature, and the time it takes for those changes to ripple through various databases and get reconciled with other kinds of information. And the realization that sometimes this reconciliation may never happen.
One of the projects that I've been working on during the past couple of years has involved developing educational materials that use bioinformatics tools to look at the isozymes that metabolize alcohol. As part of this project, I've been…
sporte | August 9, 2008Instead of enjoying a sunny summer day today, or partying with SciBlings in New York, I'm staring out my window watching the rain. Inspiration hit! What about searching for August?
Folks, meet the HFQ protein from E. coli. I found this lovely molecule by doing a multi-database search at the NCBI with the term 'August'.
HFQ is a lovely protein with six identical subunits, that's involved in processing small RNA molecules and is homologous to some eucaryotic proteins that work in RNA splicing (1).
Do you see the blue loopy regions in the center of the structure? Those are positively…
sporte | April 26, 2008Over 2600 genetic diseases have been found where a change in a single gene is linked to the disease. One of the questions we might ask is how those mutations change the shape and possibly the function of a protein?
If the structures of the mutant and wild type (normal) proteins have been solved, NCBI has a program called VAST that can be used to align those structures. I have an example here where you can see how a single amino acid change makes influenza resistant to Tamiflu®.
This 4 minute movie below shows how we can obtain those aligned structures from VAST and view them with Cn3D.…
sporte | April 17, 2008In the class that I'm teaching, we found that several PCR products, amplified from the 16S ribosomal RNA genes from bacterial isolates, contain a mixed base in one or more positions.
We picked samples where the mixed bases were located in high quality regions of the sequence (Q >40), and determined that the mixed bases mostly likely come from different ribosomal RNA genes. Many species of bacteria have multiple copies of 16S ribosomal RNA genes and the copies can differ from each other within a single genome and between genomes.
Now, in one of our last projects we are determining where…
sporte | April 16, 2008Ribosomes are molecular machines that build new proteins. This process of synthesizing a protein is also known as translation.
Many antibiotics prevent translation by binding to ribosomal RNA. In the class that I'm teaching, we're going to be looking at ribosome structures to see if the polymorphisms that we find in the sequences of 16S ribosomal RNA are related antibiotic resistance.
This is related to our metagenomics project where we investigate the polymorphisms we find in 16S ribosomal RNAs.
This 6 minute video introduces ribosomes, discusses where they're found, what they're made of,…
sporte | April 8, 2008I love using molecular structures as teaching tools. They're beautiful, they're easy to obtain, and working with them is fun.
But working with molecular structures as an educators can present some challenges. The biggest problem is that many of the articles describing the structures are not accessible, particularly those published by the ACS (American Chemical Society). I'm hoping that the new NIH Open Access policy will include legacy publications and increase access to lots of publications about structures.
It would also be great if other funding agencies, like the National Science…
sporte | April 4, 2008This morning I had a banana genome, an orange genome, two chicken genomes (haploid, of course), and some fried pig genome, on the side. Later today, I will consume genomes from different kinds of green plants and perhaps even a cow or fish genome. I probably drank a bit of coffee DNA too, but didn't consume a complete coffee genome since my grinder isn't that powerful and much of the DNA would be trapped inside the ground up beans.
Of course, microbes have genomes, too. But I do my best to cook those first.
So, what is a genome? Is it a chromosome? Is it one of those DNA fragments or…
sporte | March 19, 2008Have 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.
Introduction to Cn3D from Sandra Porter on Vimeo.
sporte | February 14, 2008Believe it or not, this is a DNA kiss.
Have a loverly Valentine's DNA!
(And just in case you're wondering, yes, I did put it on a coffee mug.)
sporte | December 28, 2007If 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 16S ribosomal RNA, about 56 nucleotides to be precise. The other partner is S15, one the proteins in the ribosome.
If we could look inside the bacteria that made these, we would see lots of other proteins binding to these two partners within a molecular machine.…
sporte | December 14, 2007Last 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%.
Paul gave me some answers…
sporte | December 7, 2007This 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 depends on the database that you're searching.
You can have more than one answer.
Now, here's the hard part. Explain why you think your answer is correct.
sporte | December 1, 2007The 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 PubChem at the NCBI. It's not an exclusive (or even last) resort but there are lots of fancy molecules hanging around, just waiting to be discovered and put onto drinking containers.
2. Now, we'll look for a molecule. I'm going to use caffeine for this example since I…
sporte | November 14, 2007This 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?
sporte | September 25, 2007Biology 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 students and co-workers spend time chatting about TV shows and…
sporte | September 11, 2007Two 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.
technorati tags: molecular models, protein structures, influenza, bioinformatics, Cn3D
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…