Nano-bio lab course: MAPs and CD

Editor’s note: Over the next several days, we will share the student impressions of some of the techniques learned in INBT’s nano-bio laboratory course (670.621). These reports demonstrate the wide variety of techniques students trained at the Johns Hopkins Institute for NanoBioTechnology are expected to understand. Each technique is taught in a different affiliated faculty lab. More lab techniques to come.

Membrane Active Proteins (MAPs) and Circular Dichroism (CD) spectrography

During this lab, we learned a couple of techniques that I had not used before. First we synthesized liposomes and processed them, resulting in uniform liposome radius. Then we made a solution of membrane active proteins with aromatic amino acids so that their absorbance and emission could be measured.

CD_trans

circular dichroism (CD) spectrography

We ran the proteins through the fluorometer at varying wavelengths to create a profile of emission and absorbance of the protein. This was done also at varying pHs and at different liposome concentrations.

In theory the proteins should incorporate into the liposomes and there should be a change in the spectra as a result. During our lab time we had issues getting the desired results, but it was still informative on how to use the fluorometer and other new equipment. We found the spectra for two different proteins at two different pH values for each to see the effect that pH had on the emission/absorbance spectra.

We also preformed CD spectrography (circular dichroism) to determine the chirality of the proteins, that is, how are the specific molecules spatially arranged. Again the procedure did not work exactly as planned, but learning how to perform the measurement was informative, nonetheless.

About the author: Jackson DeStefano is a first year PhD candidate in the laboratory of Peter Searson, professor of materials science and engineering.

For all press inquiries regarding INBT, its faculty and programs, contact Mary Spiro, mspiro@jhu.edu or 410-516-4802.
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