New for Spring 2011: BCHM 155 Biochemistry Laboratory

This Spring, the Biochemistry Department is offering a new course, BCHM 155 Biochemistry Laboratory to be taught by Prof. Emily Westover.  This lab will meet 6 hours per week and will focus on protein biochemistry.  Students will gain skills to biochemically characterize proteins, including protein purification, enzyme kinetics, and ligand binding.  For part of each module, students will design their own experiments. Students will report their work in written and oral formats.

Spring-loading the active site of cytochrome P450

Enzymes differ from other catalysts in the exceptional substrate selectivity they exhibit.  However, the active sites of related enzymes are often very similar, even though different substrates are acted upon (for example in the superfamily of cytochrome P450s).  How does a given enzyme preferentially bind a particular substrate?  In a new paper appearing in the jounal Metallomics, Chemistry grad student Marina Dang and Profs. Susan Sondej Pochapsky and Thomas Pochapsky use nuclear magnetic resonance (NMR) to identify a helical structure remote from the active site of the enzyme cytochrome P450cam that is responsive to changes in substrate.  They propose that this helix can adjust the position of residues that contact substrate in the enzyme active site, much like the spring that holds batteries in place against electrical contacts in a flashlight.

Can a “chemical rope” help treat ALS?

In this week’s issue of PNAS, Brandeis postdoc Jared Auclair and Chemistry grad student Kristin Boggio, together with Professors Greg Petsko, Dagmar Ringe, and Jeffrey Agar discuss Strategies for stabilizing superoxide dismutase (SOD1), the protein destabilized in the most common form of familial amyotrophic lateral sclerosis. Working from the hypothesis that the mechanism of the toxicity involves dimer destabilization and dissociation as an early step in SOD1 aggregation, they looked for mechanisms to stabilize SOD1 using chemical cross-linking. Cross-linking the dimer using 2 adjacent cysteine residues results in substantial stabilization of relevant SOD1 mutants.

A "Chemical rope" stabilizes SOD1 protein. Mutations that destabilize SOD1 in motor neurons are associated with familial ALS

Read more about Prof. Agar, this research, and its potential for this technique in the treatment of ALS at Brandeis NOW

Biochemistry, Biophysics and Quantitative Biology Retreat 2010

Grad students, postdocs and faculty from the Graduate Program in Biochemistry & Biophysics and from the interdisciplinary program in Quantitative Biology gathered for their Annual Retreat October 21-22, 2010 at Marine Biological Laboratory in Woods Hole, MA. See the program here.

For ClC transporters, breaking up is hard to do

Many ion channels and transporters exist as oligomers with each subunit containing a distinct transport pathway.  A classic example is the ClC family of chloride channels and transporters that are homodimeric with a pathway for chloride permeation or chloride/proton anti-port through each subunit.  Because of their dimer structure, they have come to be known as “double-barreled shotguns” for chloride movement across the membrane.

Since each subunit appears to possess the complete machinery required for transport, it is  often wondered whether ClCs need to be dimeric in order to carry out function.  In a study published last week in Nature, Brandeis researchers Janice Robertson, Ludmila Kolmakova-Partensky and Professor Christopher Miller answer this question.  By introducing two tryptophan mutations at the dimer interface, they designed a variant of a ClC transporter that could be purified and crystallized as an isolated monomer.  With this, they were able to determine that the monomer alone was fully capable of carrying out chloride and proton transport function.  These results show that the dimer is not required and that the monomer is the fundamental unit of transport in ClCs.  The question of why ClCs evolved as dimers remains a key question for understanding membrane protein structure.

2010 Beckman Scholars

active site of thymidylate kinase colored by conservation of residues between humans and Cryptosporidium parvumBrandeis was recently awarded a grant from the Arnold and Mabel Beckman Foundation through their Beckman Scholars Program. This grant will support two students each through two summers and one academic year of undergraduate research.

Philip Braunstein and Jessica Hutcheson have been named the 2010 Beckman Scholars.  Braunstein (class of 2012) is a Biochemistry major identifying parasite-selective inhibitors of pyrimidine biosynthesis in the Hedstrom laboratory.  Hutcheson (2011) is a Biochemistry/Neruoscience major investigating the molecular processes that determine memory in the Griffith laboratory.

Congratulations to the winners!

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