Showing posts with label biochemistry. Show all posts
Showing posts with label biochemistry. Show all posts

Sunday, February 6, 2011

Course: QM/MM modeling of enzymatic reactions


I am teaching a graduate course QM/MM modeling of enzymatic reactions.  Though this is about as non-basic as you can get in molecular modeling it may be of interest to some readers of this blog.

In addition to the course website, which includes a list of papers and lectures slides updated weekly, I also hope to make blog posts summarizing the in-class discussion.  This will happen over at Proteins and Wave Functions, a new group blog I have started to facilitate group communication - both within the group and with the scientific community at large (constructive comments from anyone are greatly appreciated).

Sunday, December 5, 2010

Arsenic and odd life


A recent Science paper describes "A bacterium that can grow by using arsenic instead of phosphorus", and molecular visualization is used to elegantly illustrate the basic idea, a shown in the above screencast (for the whole video visit gizmodo).

Whether the basic idea is correct is a whole other matter: for examples see here and here (be sure to check out the comments).

Wednesday, June 16, 2010

Fold.it - Solve puzzles for science

I just came across this amazing game/puzzle/software - call it what you will - Foldit.

It's an interactive protein folder that evaluates the energy on the fly to let you know how well you are doing.

But, and here is the important bit, the energy function is the same used in the Rosetta packages - a state-of-the-art protein folder (at least that's how I read it - the details are a bit sketchy). This is not a toy, but an exciting experiment to test whether human intuition and pattern recognition can compete with Monte Carlo sampling.

The screencast below (see a bigger version here) shows 6 intro puzzles that teaches you some of the techniques for protein folding. You get the program here and make an account for yourself here (making an account using Foldit did not work for me).

When you start Foldit the first time it takes you into the intro puzzles immediately (i.e. bypassing the menu).

I don't know where to start about the many implications of this program for fundamental science, teaching, and public outreach. So I'll simply say wow!, and go on to level 2-3. Not a moment to lose, CASP9 is underway you know!



June 20th, 2010 update:

Not sure why I didn't think to check youtube immediately but there are many videos about foldit. Here are a couple:

Sunday, October 18, 2009

Proteopedia


Proteopedia is just what the name suggests: a wikipedia for proteins. What makes it specific to proteins is the integration of Jmol for animated and interactive figures. It has a long list of pre-made entries ready for use in a lecture and, like a real wiki, you can add content as well.

A lot of the features are explained using a set of very nice screencast. The screencast above is simply a recording of the first 2 minutes of the first video (protopedia does not offer a way to embed the videos) narrated by Eran Hodis.

Wednesday, October 14, 2009

Ribosome Animation

For a while I thought I would be only science blog that would make it through October without mentioning the Nobel Prize. But via Chemical Blogspace I came across this video interview of the 2009 Nobel Prize co-winner in Chemistry Venki Ramakrishnan posted on The Sceptical Chymist (note: spell-check when you name your blog!):
During the interview they show some stunning molecular animations of the ribosome in action, which are credited to Said Sannuga and Ramakrishnan. I wonder ... Sure enough there are several very interesting animations on Ramakrishnan's web site. The screencast above shows a few seconds of one of them. For the rest, go to the site and have a look.

Sunday, June 14, 2009

Just one of those links


Every once in a while you come across a web page that really blows your mind. This is one of them. My first reaction was "I have to learn how to do this!", and this is what really got me interested in Jmol. It took a while, but eventually I came up with something a little bit similar (helped in no small part by this excellent tutorials page) and showed it to everyone that came within shouting distance. You can watch it on a separate page or click on the image here.



In a previous post I showed how to get the coordinate file and the html code. However, the set of commands for this animation is too lengthy to include in the html, so I used a separate script file, which can be downloaded here.

The script is kind of long but of most the lines are actually the same commands used over and over again. For example, here is how I go from a spacefilling model of the protein to just the backbone chain:

select protein
spacefill 400; wireframe 0.0; trace
spin on
set echo top center
echo A protein is long chain that is folded| in a certain way
delay 2
spacefill 300; wireframe 0.3; trace; delay 0.2
spacefill 200; wireframe 0.3; trace; delay 0.2
spacefill 100; wireframe 0.3; trace; delay 0.2
spacefill 0.0; wireframe 0.3; trace; delay 1.0
spacefill 0.0; wireframe 0.2; trace; delay 0.2
spacefill 0.0; wireframe 0.1; trace; delay 0.2
spacefill 0.0; wireframe 0.0; trace;
delay 5
spin off

The key command here is "delay x" which stops the script for x seconds and this is what drives the animation forward. x is what you play with (endlessly).

Then there is the "moveto" command which does the cool repositioning.

echo Let's have a closer look at BADX
moveto 1.0 { -109 890 -443 149.21} 245.66 0.0 0.2 {32.302 28.212 29.408} 45.037945 {0.0 0.0 0.0} 42.396088 -68.80987 50.0;


The input to the moveto command looks very intimidating, but can be generated very easily by the "show moveto" command, as I show in this screen cast.



Finally, the subject of the animated presentation is an ongoing research project. Just like in teaching, animation can be used to bring across very complicated and detailed points to the viewer. Imagine explaining the content of this animation in words! I think molecular animation is a powerful, and overlooked, recruiting tool - as long as there is some kind of guiding narration. So you can also find a link to the animation on my research page.

I have also used snippets of the animation in research talks. But there I have broken the animation into segments, and installed buttons so I can control the timing, using html. More about this in a later post.