First impression, and ω-3 fatty acids

Just arrived at Baltimore and driving through a big city is an experience very different from the kind I get at Morgantown, WV. And if that felt overwhelming, I clearly had no clue what was awaiting me at the Baltimore Convention Center. This is the first time I am attending a meeting of this stature, and the sheer magnitude of it all got me instantly! I am still struggling my way through the program book, and that doesn’t even include the challenge of finding the right conference room at the right time. I am looking at spending a significant amount of time reading through the book and fixing my meeting itinerary which I regret not having done earlier.

My highest point of the day was the talk by the mid-career award winner, Prof. Scott Feller. With a distinct touch of humor, Prof. Feller explained what makes ω-3 fatty acids special. The so-called “good fats”, which has steadily gained the support of nutrition experts, is found in high abundance in our retina and brain. Prof. Feller has sought an explanation for this fact.

He started off by explaining the influence of the structure of such polyunsaturated fatty acids on their torsional potential energy surface. These fatty acids have carbon-carbon double bonds separated by two carbon-carbon single bonds, and the double bonds always have a cis-conformation about them. With 2,5-(Z,Z) heptadiene as a model system, he used quantum mechanical calculations to show what in my opinion was the heart of his presentation: polyunsaturated fatty acids are extremely flexible. In other words, these molecules can access a large number of conformations with very little or no increase in energy. This property distinguishes it from its saturated counterparts. He then used molecular dynamics (MD) simulation to study the conformations sampled by two molecules, namely, DHA (a polyunsaturated fatty acid) and stearic acid (a saturated fatty acid). The results ratified the earlier finding.

The next step was simulation of rhodopsin mixed with either of the two fatty acids. Rhodopsin is a retinal protein. Microsecond timescale MD simulation of systems of this size demands a lot of computational resource. On the flip side, such studies can generate a lot of information that cannot be obtained by other methods. The simulations showed that DHA accumulates at the surface of the protein while stearic acid is depleted. Furthermore, the simulations hinted at the possible reason for this difference in behavior: DHA paid a smaller entropic penalty for associating with the protein. This is a direct consequence of the original finding, i.e. polyunsaturated fatty acids can easily access many conformations. The rest of the talk focused on the influence of DHA in dimerizing alpha-helical proteins, and the possibility that DHA-association destabilizes rhodopsin, a protein with very high alpha-helical content.

I have read about claims that ω-3 fatty acids can reduce the loss of agility with old age. Didn’t know that it itself was so agile!

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