Columbus Labs

Physical Determinants of β-Barrel Membrane Protein Folding in Lipid Vesicles

Linda — Wed, 04 May 2011 02:14:01 +0000

Dewald AH, Hodges JC, Columbus L. Biophysical Journal 100:2131 – 2140.
The spontaneous folding of two Neisseria outer membrane proteins, opacity-associated (Opa)₆₀ and Opa₅₀ into lipid vesicles was investigated by systematically varying bulk and membrane properties. Centrifugal fractionation coupled with sodium dodecyl sulfate polyacrylamide gel electrophoresis mobility assays enabled the discrimination of aggregate, unfolded membrane-associated, and folded membrane-inserted protein states as well as the influence of pH, ionic strength, membrane surface potential, lipid saturation, and urea on each. Protein aggregation was reduced with increasing lipid chain length, basic pH, low salt, the incorporation of negatively charged guest lipids, or by the addition of urea to the folding reaction. Insertion from the membrane-associated form was improved in shorter chain lipids, with more basic pH and low ionic strength; it is hindered by unsaturated or ether-linked lipids. The isolation of the physical determinants of insertion suggests that the membrane surface and dipole potentials are driving forces for outer membrane protein insertion and folding into lipid bilayers.

The Columbus Laboratory moved to the new Physical Life Science Building

Linda — Thu, 12 Jan 2012 05:27:56 +0000

The Columbus laboratory moved to beautiful new space on January 3, 2012. Here are some pictures of the new space.

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Linda Columbus

Linda — Mon, 18 Feb 2008 22:33:35 +0000

PI

Postdoctoral Research: The Scripps Research Institute
Advisors: Kurt Wuthrich and Scott Lesley
NMR and X-ray crystallography of Membrane proteins.

PhD: The University of California Los Angeles (2001)
Advisor: Wayne Hubbell
Mapping protein backbone dynamics with EPR Spectroscopy and site – directed spin labeling.

BA, high honors: Smith College (1996)
Advisor: David Bickar

Professor Columbus is interested in accelerating membrane protein techniques to investigate the structure and dynamics of membrane proteins involved in bacterial pathogenesis.

Linda Columbus’ CV

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Structural origins of nitroxide side chain dynamics on membrane protein α-helical sites

Linda — Sun, 24 Oct 2010 20:20:33 +0000

Kroncke BM, Horanyi PS, and Columbus L. Structural origins of nitroxide side chain dynamics on membrane protein α-helical sites. Biochemistry 49:10045–10060 (2010)

Two graduate students and an undergraduate join the lab

Linda — Tue, 10 Jan 2012 20:41:13 +0000

This semester Jennifer Martin and Ashton Brock joined the laboratory as first-year graduate students. Jen’s research focuses on Opa proteins and Ashton’s research investigates the effects of detergents on the structure and function of membrane proteins.

Undergraduate Elleansar Okwei also joined the lab and is working with Dr. Carol price on determining the function of proteins with known structure, but unknown function.

Structure of the GLD-1 homodimerization domain: insights into STAR protein-mediated translational regulation.

Linda — Sun, 04 Apr 2010 20:27:44 +0000

Beuck C, Szymczyna BR, Kerkow DE, Carmel AB, Columbus L, Stanfield RL, Williamson JR. Structure of the GLD-1 homodimerization domain: insights into STAR protein-mediated translational regulation. Structure 18:377-89 (2010).

Alison and Jackie’s paper #15 of the “Top 25 Hottest Articles” in Biophysical Journal

Linda — Wed, 09 Nov 2011 19:37:43 +0000

According to Science Direct, from April to June 2011

Physical Determinants of Beta-Barrel Membrane Protein Folding in Lipid Vesicles
Biophysical Journal, Volume 100, Issue 9, May 2011, Pages 2131-2140
Dewald, Alison H.; Hodges, Jacqueline C.; Columbus, L.

is 15th in the “Top 25 Hottest Articles” of Biophysical Journal.

Ashton Brock

Linda — Sat, 19 Nov 2011 22:03:12 +0000

Graduate Student

BS: Chemistry, Winthrop University (2011)
Ashton conducted undergraduate research with Dr. Takita Sumter on the regulation of High Mobility Group A1 proteins involved in colon cancer.

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Kalyani Jambunathan

Linda — Mon, 18 Feb 2008 22:24:14 +0000

Dr. Jambunathan is currently a postdoctoral fellow at SRI in Harrisonburg, VA.

Postdoctoral Fellow

PhD: University of Virginia, Charlottesville, VA (2007)
Advisor: Dr. H.Mario Geysen
Antibody epitope binding modes at single amino acid resolution.

MS: Indian Institute of Technology, Tamilnadu, India (2001)
Advisor: Dr. T.S. Chandra
Vermicomposting of Sugar Industry residues- A Biochemical Analysis.

BS: Madras Christian College, Tamilnadu, India (1999)

Mixing and Matching Detergents for Membrane Protein NMR Structure Determination

Linda — Sat, 09 May 2009 05:13:03 +0000

Columbus L, Lipfert J, Jambunathan K, Fox DA, Sim AYL, Doniach S, and Lesley SA. Mixing and Matching Detergents for Membrane Protein NMR Structure Determination J. Am. Chem. Soc. 131:7320–7326 (2009)

Justin and Ashley graduate with highest distinction and awards

Linda — Sun, 29 May 2011 18:41:37 +0000

On Sunday, May 22, 2011, Ashley Keller and Justin Kim graduated with a B.S. degree in Chemistry with a Biochemistry focus. They both participated in the Chemistry Department’s Distinguished Major Program and graduated with highest honors for their research and academic performances. In addition, Ashley was awarded the Alpha Chi Sigma Chemistry Award and Justin was awarded American Chemical Society ~ Virginia Section Award and the Robert Bryan Undergraduate Teaching Award.

Properties of Membrane Proteins

Linda — Sat, 13 Sep 2008 18:15:33 +0000

In the field of structural biology, membrane proteins represent a significant challenge, and in recent years new structural and biochemical tools have been developed to characterize these systems. In this review, we discuss the functions and properties of membrane proteins, and we discuss the approaches and tools that yield new information on their structure and molecular function.

David Shultis

Linda — Fri, 05 Jun 2009 18:15:31 +0000

Dr. Shultis is currently a postdoctoral fellow in Tom Walz’s Laboratory

Postdoctoral Fellow

PhD: University of Virginia, Charlottesville, VA (2008)
Advisor: Dr. Michael C. Wiener
X-ray Crystallographic and NMR spectroscopic studies of energy dependent membrane protein complexes.

BS: Aeronautical Science Embry-Riddle Aeronautical University (1993)

Brett receives 2011-2012 GSAS Dissertation Year Fellowship

Linda — Thu, 19 May 2011 12:53:12 +0000

Brett received one of the 20 Graduate School of Arts & Sciences Dissertation Year Fellowships awarded this year. The fellowship includes a stipend for his final year of study in the laboratory. The awardees were selected first by their department and then by a college committee. Students are selected based on their academic performance, research accomplishments, and contributions to the university and scientific community.

Structure and ligand binding of the soluble domain of a Thermotoga maritima membrane protein of unknown function TM1634

Linda — Sat, 01 Mar 2008 02:15:21 +0000

McCleverty C*, Columbus L*, Kreusch A, Lesley SA. Structure and ligand binding of the soluble domain of a Thermotoga maritima membrane protein of unknown function TM1634. Protein Science 17:869-77 (2008).