Barry and Dogic receive 2010 Cozzarelli Prize

Physics graduate student Edward Barry and Professor Zvonimir Dogic have been selected to receive the 2010 Cozzarelli Prize in Engineering and Applied Sciences from the Proceedings of the National Academy of Sciences (PNAS) for their work entitled “Entropy driven self-assembly of non-amphiphilic colloidal membranes.”

The work of Barry and Dogic was selected for exploring a novel pathway for the self-assembly of 2D fluid-like surfaces or monolayer membranes from non-amphiphilic molecules. Amphiphilic molecules consist of immiscible components, such as a hydrophobic tail and a hydrophilic head, which are irreversibly linked to each other, thus frustrating their bulk separation. When added to water, these molecules self-assemble into a variety of structures in order to satisfy competing affinities for the solvent. One particular structure, a bilayer membrane, which is a thin flexible sheet with remarkable mechanical and chemical properties, plays an essential role in biology, physics, and material science. Over the past decade the paramount example of conventional amphiphilic self-assembly has inspired the synthesis of numerous amphiphilic-type building blocks for studies of membrane self-assembly including various block-copolymers, heterogeneous nanorods, and hybrid protein-polymer complexes. Underlying all of these studies is the belief that amphiphilic molecules are an essential requirement for membrane assembly.

Barry and Dogic, using a combination of theory and experiments, describe for the first time a set of design principles required for the assembly of non-amphiphilic membranes in which the constituent rod-like molecules are chemically homogeneous.  Using a simple mixture of filamentous bacteriophages and non-adsorbing polymer, they were able to assemble macroscopic membranes roughly 4-5 orders of magnitude larger than the constituent molecules themselves. Due to unique properties of their system, Barry and Dogic were able to characterize the physical behavior of the resulting non-amphiphilic membranes at all relevant length scales and provide an entropic mechanism that explains their stability. The importance of these results lies in their potential to establish a fundamentally different route toward solution based self-assembly of 2D materials.

Papers selected for the Cozzarelli Prize were chosen from more than 3,700 research articles published by PNAS in 2010 and represent the six broadly defined classes under which the National Academy of Sciences is organized. The award was established in 2005 and named the Cozzarelli Prize in 2007 to honor late PNAS Editor-in-Chief Nicholas R. Cozzarelli. The annual award acknowledges recently published papers that reflect scientific excellence and originality. The 2010 awards will be presented at the PNAS Editorial Board Meeting, and awardees are recognized at the awards ceremony, during the National Academy of Sciences Annual Meeting on May 1, 2011, in National Harbor, Maryland.

An alternative to scuba diving

Many promising medicinal agents (anti-cancer, anti-bacterial, anti-viral and anti-fungal) have been discovered among the diverse molecules produced by marine organisms. However, scuba-diving to harvest sponges and algae is not usually a practical way of obtaining usable quantities of these compounds, especially if they are present only in trace quantities in the source organisms.

A recently published paper in Organic Letters from the laboratory of Assistant Professor of Chemistry Isaac Krauss is the first to present a synthetic laboratory approach to the preparation of the bromophycolides, originally isolated from Callophycus Serratus, a red algae which was collected off the coast of Fiji. Although these compounds were shown to posses anti-tumour, anti-HIV and anti-malarial properties, algae collected in a second expedition to Fiji apparently contained none of the natural product (hence the desirability of a laboratory synthesis). The bromophycolides are a structurally unique family of natural products containing brominated asymmetric carbon centers and large 19-membered rings. This paper illustrates the preparation of the bromophycolide A and D ring system in high enantiomeric purity via a short (9-step) synthetic sequence.

More “Noted in Press”

Brandeis authors noted in boldface.

New route to lycopodium alkaloids

The lycopodium alkaloids are a large and extensively studied alkaloid family. Huperzine A (1), the medicinally most significant lycopodine alkaloid as a potential treatment for Alzheimer’s disease, functions as an acetylcholinesterase inhibitor but may have other roles as has been addressed in several recent reviews.  Sauroine (2, 7,8-dihydroxylycopodine), from Huperzia saururus, was reported in 2004 and shown in 2009 to improve memory retention in the step-down test in male Wistar rats, significantly increasing hippocampal plasticity. 7-Hydroxylycopodine (3), from Huperzia serrata, was also reported in 2004 and may have related biological activity.

In their recent Organic Letters paper entitled the Synthesis of (±)-7-Hydroxylycopodine, the Snider lab at Brandeis developed a new general route to these bridgehead hydroxylated lycopodines. They reported a practical six-step synthesis of 7-hydroxylycopodine which makes it readily available for further biological evaluation. The key step of the synthesis is the treatment of bicyclic enol ether 4 with 60% sulfuric acid that affords tricyclic amino alcohol 5, which is further elaborated to 7-hydroxylycopodine (3) in three steps. The application of this route to the synthesis of sauroine (2) is now under investigation.

Even more science

New journal articles from Brandeis students, postdocs and faculty, for which we didn’t find the time to write individual articles on this blog. Brandeis authors shown in boldface.

and more...

Biochemistry Senior Research Talks

It’s also the season for Senior Honors / Masters Thesis talks…


Annual Senior Research Talks
2009/2010 Biochemistry Honors and BS/MS Candidates

Friday, April  23, 11:30-1:30pm – G-zang 122

Clarence Friedman – BS/MS

Characterization of 1-d-deoxyxylulose reductoisomerase
Advisor: Dan Oprian

Stefan Isaac  – BS/MS

Functional Characterization and in silico Modeling of HlyU
Advisors:  Dagmar Ringe/Greg Petsko

Seth Lieblich BS/MS

Bacterial Gene Repressors
Advisor: Dagmar Ringe

Miranda Patton BS/MS

Mutation of the Active Site of IMP Dehydrogenase, to Find a Novel Mutant and Create a Hybrid GMP Reductase
Advisor:  Liz Hedstrom

Nat Lazar BS

We are superfamily: bioinformatic and biochemical analyses of protein evolution
Advisor:  Douglas Theobald

Kanchana Ravichandran BS

Formation of heterotetramers between the human isozymes of Inosine 5’-Monophosphate Dehydrogenase
Advisor:  Liz Hedstrom

Seth Robey BS

Streamlining C1C-0 Purification and Examining the pH Dependence of an Amino Acid Transporter
Advisor:  Chris Miller

Kenta Yamamoto BS

The Type-1 Insulin-Like Growth Factor in Cancer and Hematopoiesis
Advisor: Ruibao Ren

Everyone is welcome and encouraged to come.  Pizza will be provided.

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