Biocurious is a weblog about biology, quantified.

BioImage Highlights

by Andre on 25 July 2005

So BioImage is over and I think it was definitely a great success. The talks were interesting and I came away with what I think are some good ideas, although that obviously remains to be seen. I won’t talk about all of the talks since there were quite a few, but I will mention a few that I found particularly interesting over the next couple of days. First up: Hermann Gaub.

He is one of the pioneers of single protein AFM pulling experiments so I was quite interested in what he had to say about that. I really like these experiments on single bacteriorhodopsin molecules.* One of the reasons is that unlike with most AFM pulling experiments, by imaging the surface before and after pulling it is possible to unambiguously determine that the force trace was indeed due to a single unfolding protein. They were also able to observe a definite sequence of unfolding since most of the protein remains stuck in the membrane and doesn’t unfold. Again, this is in contrast to most pulling experiments in which similar domains of a multi-domain protein unfold in a random order. Given that natural membranes know the difference between inside and outside they were also able to unfold from the other side and observe the opposite unfolding sequence. Overall a very cool experiment in my opinion.

He also described some mechanical experiments that can be parallelized by eliminating the cantilever in favor of a single elastic molecule and observing bond rupture indirectly by fluorescence. The paper can be found here. You can also stay tuned for an upcoming paper of theirs on this sensor which he said will appear in PNAS in October.

*From his site, click on single molecule biophysics and then combined imaging and unfolding at the bottom of the page for some images of the membranes and a brief description.

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