University of Science and Technology of China
I was admitted as one of the 100 students of the 2007 National Physical Chemistry Summer School for Graduate Students. Held in University of Science and Technology of China, Hefei, a less developed city in central China, the 3-week summer school is poor organized. We have only lectures here, no workshop, no communication among students, no visit to the famous national laboratory (Hefei National Laboratory for Physical Sciences at the Microscale. Maybe some of you chemists would hear of this laboratory from some Angew. Chem. Int. Ed. papers). Furthermore, we have no computers here so I have to type this blog in one of the cybercafe outside the campus. However, up till now all of the lectures given are insightful and thought-provoking, despite the variaty of disciplines and my lack of mathematic proficiency. I will blog about some of the lectures I attend in the several posts.

The first lecture was given by Prof. Yang Yuliang. He conveyed the concept that physical chemistry is the key to the myth of biology. He introduced some of his research as examples.

Scheme of the self-assembly of the TMV. From BIODIDAC website.
Nature is the most professional and versatile self-asembly designer. Although human has now known some superficial aspect of self-assembly, we still sometimes rely on nature templates such as insect wings and virus, especially the tobacco mosaic virus. The interesting issue about this living mono-dispersed nanorod is how the RNA chain threads into the self-assembled protein tubule, whose length is determined by that of the RNA. Although the virus was identified early in the 1930s, no detail about this process is researched, said Prof. Yang, who called the traditional biological research as nothing but ‘impulsion and illusion’. Though lack of physical data in the literature, Prof. Yang found an analogue in recent supramolecular chemistry, the threading of polyethylene glycol (PEG) chain into the cavity of alpha-cyclodextrin (alpha-CD). Alpha-CD is able to be threaded on to PEG chain in a head-to-head style to form a so-called molecular necklace (Nature 1992, 356, 325-327. doi: 10.1038/356325a0), whose length is determined by that of the guest PEG chain (molecualr weight). This feature is very similar to the self-assembly of TMV. Prof. Yang construct a mathematical model based on the alpha-CD/PEG system (which is too mathematical for me to describe here). Their model has succeeded in confirmation of the thermodynamic data of the threading process. ‘If there were enough thermodynamic or any other physical data about the assembly of TMV, we would develop a physical approach to solve the problem too.’, said Prof. Yang. I raised my temperature once I see the figure of the alpha-CD/PEG system because this is exactly the field I’m doing currently, while I have never imagine any relationship of my work to virus!

He also related the problem of the many polyhedron morphologies of virus to the generalized Thomson Problem – how to arrange a number of ball on a spherical surface at minimum energy. Applying the Sefl-Consistent Field Theory on a curve surface, Prof. Yang and co-workers were able to explain why so many virus can have such symmetric shapes in nature. Their work was published on Phys. Rev. E, 2006.

I will continue talking about Prof. Yang’s interesting ideas on biological system in the next post.