Macromolecular Modeling Blog ™

Stu Borman wrote a nice piece in Chemical & Engineering News (CEN) highlighting a recent paper in Nature Chemistry that presents the work of a collaboration between the Tezcan Lab at UCSD and the Rosetta Design Group. In this work, a monomeric protein was redesigned to become capable of forming metal and pH tunable nano- to micro- scale sheets, tubes, and other assemblies.

Mr. McGuire: I just want to say one word to you. Just one word.

Benjamin: Yes, sir.

Mr. McGuire: Are you listening?

Benjamin: Yes, I am.

Mr. McGuire: Plastics. Proteins.

Benjamin: Exactly how do you mean?

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Traditionally, computational protein design efforts have been directed at calculating a single sequence predicted to fold to a particular target structure. Recently, however, a number of conceptual generalizations have been pursued, ranging from the use of backbone flexibility, off-rotamer side chain flexibility, negative design, multi-body potentials, conformational free energy, and prediction of sequence profiles. Below I present our state-of-the-art research whose goal is to understand how protein sequences are optimized to be compatible with binding multiple partners with high affinity. – By Menachem Fromer.

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Macromolecular systems engineering can help us meet some of the most important technological challenges in the world today, ranging from medicine to renewable energy, and the development of better-integrated computational design tools will accelerate progress. Macromolecular modeling capabilities are advancing rapidly, but much of their potential for supporting systems engineering has yet to be exploited. In this post, I’d like to describe the fundamental nature of the problems and outline some of what needs to be done to make their potential a reality. By Dr. Eric Drexler.

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In a recent Nature paper Koder & Anderson et al. describe the procedure for creating an O2 transport protein from first principals. The paper is somewhat technical and may appeal to the biochemists amongst our readers, here we present the main ideas, findings and conclusions. 

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Although numerous structures of peptide bound MHC-II molecules were solved, no one knows how does the peptide free MHC look like. Painter et al. elegantly use molecular dynamics to model the conformational changes upon peptide removal. Most interestingly a helix from the peptide binding domain adopts the binding mode of the antigen peptide. They successfully validate their model using antibodies and superantigens, predicted to differentially bind peptide-bound/free molecules according to their model. We take the validation one step further and propose mutations based on Painter’s model that would stabilize the free MHC. Will it work? Who will pick up the gauntlet?

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