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Dr. Jonathan Southard
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Electronic Mail Address:
southard@iup.edu Send me mail
CONTENTS
Course
Information for Spring 2010:
CHEM
102, College
Chemistry II (lecture section B01) -
click for course website
CHEM
102, College Chemistry II Laboratory
sections B08 & B10 (no online information)
BIOC 302,
Biochemistry II - click for course website
CHEM 600, Seminar (no online information)
Office
Hours & Course Schedule:
Office
Hours for Spring
2010
Room 239D, Weyandt Hall
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Monday
and Wednesday Thursday |
10:00 am to 11:30 am 1:00 pm to 3:00 pm |
Other hours by appointment, or stop by. (but not when I'm teaching, see the course schedule below)
Course
Schedule for Spring
2010
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CHEM
102 College Chemistry II Lab, Sec. B08, Wey 147 |
T |
2:30-4:25 |
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CHEM
102 College Chemistry II Lab, Sec. B10, Wey 147 |
W |
8:00-9:55 |
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BIOC
302 Biochemistry II, Wey 149 |
T, R |
9:30-10:45 |
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CHEM
102 College Chemistry II Lecture, Sec. B01, Wey 32 |
M, W, F |
1:25-2:15 |
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CHEM
600 Seminar |
F |
3:35-4:25 |
Research
& Other Professional Interests:
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Studies of Growth Hormone Binding Protein
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Mushrooms That Glow In The Dark
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Seeing Molecules In Three Dimensions
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Studies of
Growth Hormone Binding Protein (GHBP)
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The
known structure of Four
amino acid residues that |
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Most of the research activities in my laboratory focus on studies of growth hormone binding protein (GHBP). This protein is present in the blood of vertebrates where it binds to the protein hormone growth hormone (GH). In at least some species, notably the mouse and the rat, GHBP is also present on the membranes of various cells. Little is known about how GHBP is attached to the membranes or what it may be doing there. Our overall goal is to answer these questions. Some of our studies are reported in an article that includes research by three IUP undergraduate students and two IUP graduate students: RJ Cerio, F Xing, RJ Fatula, DE Keith, X Yang, F Talamantes, and JN Southard (2002) "Structurally distinct membrane-associated and soluble forms of GH-binding protein in the mouse". Journal of Endocrinology 172: 321-331.
To date, we have shown that GHBP is probably held on the membrane by interactions with another protein in the membrane. Based on several pieces of evidence, we have identified the integrins as prime suspects for the protein that holds GHBP to the membrane. This is a group of about 20 related proteins involved in sending signals across cell membranes. They are particularly interesting because, unlike most signaling molecules in membranes ( or 'receptors'), integrins send signals in both directions. Changes in the cell's surroundings are communicated to the cell interior and can cause various changes in cell behavior. Changes within the cell can be communicated through the integrins in the opposite direction, resulting in changes in how the cell interacts with the material surrounding the cell (the 'extracellular matrix'). These interactions are important in determining a number of cell properties including growth rate, shape, and whether the cell will be free to move or be anchored to a particular position.
In performing these tasks, integrins interact with many other proteins. Some of them recognize a sequence of three amino acids (arginine-glycine-aspartic acid or R-G-D for short) on proteins outside the cell. This sequence is present in GHBP from mouse and rat. The figure above shows the predicted location of the RGD sequence in mouse GHBP. The three amino acids are exposed on the surface so that an integrin will be able to 'see' them and interact with GHBP.
We have begun to identify the subtle differences in structure between the forms of GHBP in the blood and on cell membranes. Our earlier studies found only one difference between the two forms - the blood form has more carbohydrate on it. Recently, Chandra Kollu, a Chemistry M.S. student, developed a method to cleave GHBP specifically at one spot, about halfway along the polypeptide chain. By careful analysis of the resulting fragments, we were able to see two differences in the structure of blood and membrane GHBP. In addition to the different amounts of carbohydrate, they appear to differ in the number of amino acids in each chain.
Currently, we are beginning studies that will take advantage of a synthetic form of GHBP (produced by a recombinant DNA in insect cells) to study how the structure of GHBP affects its interactions with cell membranes.
Mushrooms That Glow In The Dark
Omphalatus olearius photos from Tom Volk's fungus page. (http://www.wisc.edu/botany/fungi/volkmyco.html)
Since a very young age, I've been fascinated by the many strange forms of life that surround us. I guess this basic interest had a big part in my eventual choice of a career (although I did seem to drift around a bit on the way). My family enjoys getting outdoors whenever we can, and in the past we lived in places (the central coast of California & northern Idaho) with climates where mushrooms really grow wild. So, we became interested in fungi & then became friends with a mycologist who could help us identify what we found (a real advantage if you are interested in eating any of these things). Being a fungiphile really changes your attitude to the weather - wet and dank weather now becomes perfect.
Anyway, western Pennsylvania is pretty good for fungi and one of the first ones we found after moving here was Omphalotus olearius, common name = Jack-o-lantern mushroom. As you might expect, they are pumpkin orange, but what really makes them wierd is that they glow in the dark. Turns out that this is the largest of several luminescent fungi. Quite a bit is known about the chemistry of bioluminescence in fireflies and a couple other species, but as far as I can tell, very little has been done in fungi. I think it would be interesting to see how the process in these fungi works. So far however, I've only had time to do a little literature research in this area.
CAUTION: These mushrooms are NOT edible. You should never consume any wild mushroom unless you are absolutely sure of it's identity. Many can make you quite sick and a some are very deadly.
Seeing
Molecules In Three Dimensions
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Biochemistry is all about
understanding the invisible world of atoms and molecules that make up
living organisms. When I began studying biochemistry, our ability
to picture the structures of large biomolecules like proteins was at a
very primitive stage. It is now possible for anyone with access
to the internet to obtain and analyze the structures of thousands of
these molecules. I use tools for molecular visualization and analysis both in my research and in my teaching. The pictures shown here are examples of what can be done using my current favorite resource. Chimera is a fairly easy-to-use, but very powerful tool for visualization and analysis of biomolecule structures.
Detail of the atoms at the interface between the two molecules of mouse GHBP (near the bottom of the complex shown to the left). |
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Maintained by southard@iup.edu
Last modified
on December 30, 2009.