Category Archives: Biochemistry and Biophysics

Motor proteins—and people—can change directionality

It took three years of adventures after college—including stints as a ski instructor, barista and a commercial chemist—before Andrew Popchock knew that he wanted to return to the lab to pursue a PhD at OSU’s Department of Biochemistry and Biophysics.

Two microtubules slide across each other by the walking of motor proteins sandwiched between them

Andrew’s research takes place at Dr. Weihong Qiu’s Single-Molecule Biophysics Laboratory and focuses on kinesin-14s—motor proteins found in eukaryotic cells. These motor proteins in cells travel along microtubules to create and maintain the mitotic spindle, which are macromolecular structures that are responsible for chromosome segregation during cell division.

By using an imaging technique called TIRF microscopy, a team of researchers from Dr. Qiu’s lab discovered that a kinesin-14 found in fungus cells called KlpA can change direction along its cytoskeleton tracks. KlpA is the first motor protein of its kind that researchers have discovered that demonstrates this type of bidirectional movement. The results of their study were recently published in Nature Communications.

Total Internal Reflection Fluorscence (TIRF) microscopy image of two microtubules sliding across each other

The motor protein that Andrew studies could be important in helping researchers understand cancer growth. This could have implications for drug treatment therapy, potentially guiding the creation of motor protein-based molecular devices for more controlled drug delivery in cancer treatments.

 

Andrew on the Oregon Coast

Growing up, Andrew was interested in physics and biology, but it wasn’t until he worked in a lab under the direction of a graduate student at Washington State University that he began to consider graduate studies. While working as a chemist in Idaho, he realized that he quickly reached the limit of his creative capacity and that returning to a laboratory as a graduate student at OSU would help him continue to develop his skills as a researcher.

To learn more about Andrew’s research and his path to graduate school, tune in to hear our conversation on Sunday, May 14th at 7:00 pm on 88.7 FM KBVR Corvallis or listen live online.

Elucidating protein structure with crystals

Kelsey in the lab pipetting one of her many buffers!

Proteins are the workhorse molecules of the cell, contributing to diverse processes such as eyesight, food breakdown, and disabling of pathogens. Although cells cannot function without helper proteins, they’re so small that it’s impossible to view them without the aid of special tools. Proteins are encoded by RNA, and RNA is encoded by DNA; when DNA is mutated, the downstream structure of the protein can be impacted. When proteins become dysfunctional as part of disease, understanding how and why they behave differently can lead to the development of a therapy. In Andy Karplus’ lab in the Department of Biochemistry & Biophysics, PhD candidate Kelsey Kean uses a technique known as protein x-ray crystallography to study the relationship between protein structure and function.

Protein crystals. On the left, each blade making up this cluster is an individual crystal that needs to be separated before we can use them.

Protein diffraction. An individual crystal is placed in front of an x-ray beam and we collect the diffraction resulting from the x-ray hitting each atom in the protein crystal . Using the position and darkness of each spot (along with some other information), we can figure out where each atom in the crystal was originally positioned.

An electron density map. After collecting and processing our diffraction images, we get an electron density map (blue)- this shows us where all the electrons for each atom in the protein are- and this guides us in building in the atomic coordinates (yellow) for each part of the protein. It’s like a puzzle!

Crystallization of protein involves many steps, each of which presents its own unique challenges. A very pure protein sample is required to form an ordered crystal lattice, and hundreds of different buffer solutions are tested to find the ideal crystallization conditions. Sometimes crystals can take weeks, months, or a year to grow: it all depends on the protein. Once a crystal is obtained, Kelsey ships it to the synchrotron at Lawrence Berkeley National Laboratory, which provides a source of ultra powerful x-ray light beams. Exposure of the protein crystal to x-ray light results in a diffraction pattern, which is caused by the x-ray light diffracting off of all the atoms in the crystal. A map of electron density is generated from the diffraction pattern, and then the electron density map is used to determine where the atoms are located in the protein, like a complex puzzle. X-ray protein crystallography is really amazing because it allows you to visualize proteins at the atomic level!

In addition to her lab work, Kelsey is extensively involved in teaching and STEM outreach. For the past 3 summers, she has organized a week-long summer biochemistry camp through STEM Academy, with the help of a group of biochemistry graduate students. Kelsey has also been involved in Discovering the Scientist Within, a program providing 150 middle school girls with the opportunity to perform science experiments, including isolation of strawberry DNA and working with mutant zebrafish.

Kelsey completed her undergraduate degree in biochemistry with a minor in math at the University of Tulsa, where she was also a Division I athlete in rowing. She attributes her work ethic and time management skills to her involvement in Division I athletics, which required a significant commitment of time and focus outside of lab and coursework. During one summer when she wasn’t busy with competitive rowing, she performed experiments related to protein crystallography at the Hauptman-Woodward Medical Research Institute associated with the University at Buffalo.

Kelsey knew she wanted to pursue science from an early age. She grew up surrounded by scientists: her mom is a biochemist and her dad is a software engineer! She recalls playing with Nalgene squirt bottles as a kid, and participated in the Science Olympiad in middle school, where she engineered a Rube Goldberg machine. She cites early exposure to science from her family as one reason why she feels strongly about STEM outreach to students who might not otherwise receive encouragement or support. In the future, Kelsey would like to teach at a primarily undergraduate institution.

Please join us this Sunday, April 23rd on KBVR Corvallis 88.7FM at 7 pm PST  to hear much more about x-ray protein crystallography, STEM outreach, and to hear an awesome song of Kelsey’s choosing! You can also stream this episode live at www.kbvr.com/listen.

Kean on Science!

This evening on our special pre-Inspiration Dissemination interview, we had a wonderful conversation with Kelsey Kean, a PhD candidate in the department of Biochemistry & Biophysics. While discussing the Tsoo King Lecture series, we stumbled into a myriad of tangential topics including CRISPR/Cas9 and Peter Walter’s discovery machine. As promised, we’re including some links to more information here. Click away for some awesome reading, watching, and listening!
TsooKingFlyer

Tsoo King Lectures with Peter Walter; Vilcek Award winner on the unfolded protein response

CRISPR-Cas9, revolutionary tool for genome editing.

 

Looking For the Link Between Centromeres and Cancer

DNA, the “building blocks of life”, can be bent and broken. While it is the source code for every creature on the earth, DNA is also the source of some of the most difficult diseases that plague humanity. Tonight at 7PM PST, Steve Friedman joins us from the department of Biochemistry and Biophysics to discuss characterizing centromeres of a filamentous fungi called Neurospora crassa. Centromeres, the part of the chromosome that is targeted by proteins that aid in cell division, are studied to understand how genetic mutations and resulting abnormalities in cells can lead to genetic disease and cancer.

Flasks containing strains of Neurospora crassa

Flasks containing strains of Neurospora crassa

Fungi serve as a model organism for the study of centromeres in Steve’s work because their genetic code is more complex than the yeast (Saccharomyces cerevisiae) that have been used in older studies, but still easier to study and understand than the complicated human genome.

Understanding how the human genetic code controls the production of proteins that are implicated in diseases like cancer, and how these proteins relate to centromeres that are crucial parts of a natural and healthy process of cell division, is the long term goal of such research.

To learn more about Steve and his work, tune in at 88.7 KBVR FM, or stream the show live!

microscopy images of GFP/RFP tagged centromere proteins (taken in Galya Orr's Lab at PNNL)

Microscopy images of GFP/RFP tagged centromere proteins (taken in Galya Orr’s Lab at PNNL).

Steve enjoys some time away from the lab

Steve enjoys some time away from the lab