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Postdoctoral Fellow or Research Scientist - University of Iowa

1/15/2019 4:56:04 PM CPLC Staff

University of Iowa is looking for motivated researchers to carry out projects that will provide a greater understanding of the coordinated and dynamic nucleoprotein transactions critical for high fidelity DNA repair and replication. The goal is to dissect the mechanisms that funnel “normal” DNA repair intermediates into “rogue” processes that destabilize the genome and lead to cancer, cell death and/or emergence of chemotherapeutic resistance, and to be able to manipulate these processes in development of new cancer therapies. The projects range from biochemical reconstitutions of DNA recombination, repair and replication reactions and structural and single-molecule analyses of the proteins and enzymes coordinating these reactions, to development of new single-molecule technologies and combined HTS/CADD campaigns that identify scaffolds that can be developed into potent inhibitors of human DNA repair proteins.

The ideal fit for the aforesaid position is a postdoctoral researcher with a background in single-molecule biophysics, structural biology, molecular biology or biochemistry of protein-nucleic acid interactions and a desire to extend their expertise in these areas, and/or to branch into drug discovery.

University of Iowa, Carver College of Medicine provide ample opportunities for cutting edge, interdisciplinary and collaborative research. It is an excellent environment for postdoctoral studies. Iowa City is also a delightful town to live in. It is consistently ranked among the best college towns to live in US, is a home to the internationally recognized writers’ workshop, IDT and is quite affordable.

Interested candidates can contact

Maria Spies, PhD

Professor of Biochemistry and Radiation Oncology
Carver College of Medicine
University of Iowa
51 Newton Rd., 4-532 BSB
Iowa City, IA 52242


Phone: +1-319-335-3221
Lab Phone: +1-319-335-3223
Fax: +1-319-335-9570

Another postdoctoral position is available with Dr. Ashley Spies.

His research group focuses on innovative approaches to structure-based drug discovery, employing advanced molecular dynamics simulations as well as experimental biophysical methods such as SPR and X-ray crystallography to further the understanding of complex protein-ligand interactions.They are seeking a postdoctoral researcher with a background in X-ray crystallography and/or expertise in SPR, NMR or ITC, who would like to work at the interface between computational and experimental biophysical chemistry.

In late 2019 the M A Spies group is moving into a new state-of-the art Pharmacy building, which will house the Medicinal and Natural Products Chemistry division:

Interested candidates should contact Professor M. Ashley Spies at


2/12/2014 Siv Schwink

Escherichia coli, a rod-shaped bacterium commonly found in the lower intestines of humans and other warm-blooded animals, varies widely in the number of flagella on the surface of any individual bacterial cell. Flagella—rotating whip-like structures driven by reversible motors— rotate in a counterclockwise direction to propel the bacterial cell in a swimming motion called “running”. When at least one flagellum moves in a clockwise direction, the cell begins to “tumble”, changing its directional course.

E. coli is able to control the time it spends swimming or tumbling to move towards a nutrient, such as glucose, or away from certain harmful chemicals. However, the details of how the number of flagella and the direction of rotation—clockwise or counterclockwise—influence the motion of the bacterium are not fully understood.

Now a research team led by biological physicists Yann Chemla at the University of Illinois and Ido Golding at Baylor College of Medicine has experimentally demonstrated that individual flagella on the same E. coli cell tend to move in a coordinated way, whether swimming or tumbling. The team used “optical tweezers” to immobilize individual E. coli cells under a microscope, enabling for the first time simultaneous tracking of both swimming behavior and flagellar motion for long durations.

Tumbling, the team observed, could be caused by a single flagellum stopping a run, but it often involves a concerted effort by many of the cell’s flagella. Based on their observation that E. coli cells with more flagella spend less time tumbling than would be predicted if a single flagella always “vetoed” a run, the team proposes a new mathematical relationship between the number of flagella on the cell, the direction of rotation, and the resulting probability that the cell will tumble.

Artist's conception of a swimming E. coli cell trapped in place by two optical traps: Next to the optical traps is a sequence of images showing fluorescently labeled flagella on a trapped cell. Below the traps is a representative data trace obtained from the optical traps. Image courtesy of Yann Chemla
Artist's conception of a swimming E. coli cell trapped in place by two optical traps: Next to the optical traps is a sequence of images showing fluorescently labeled flagella on a trapped cell. Below the traps is a representative data trace obtained from the optical traps. Image courtesy of Yann Chemla
This work shows that swimming behavior in bacteria is less affected by variations in the number of flagella than expected.

Chemla explains, “What we’ve found is that E. coli has developed a mechanism that makes it relatively insensitive to variations in flagellar number. A cell will run and tumble about the same regardless of how many flagella it has—which is a good thing. Otherwise cells with few flagella would run too much, and cells with many flagella would tumble too much.”

This phenomenon may provide evolutionary advantages to E. coli.

“These cells need to be swimming and tumbling at an optimal frequency to survive,” continues Chemla. “If it runs too much, it can move away from areas with lots of nutrients or toward areas that may be toxic with no mechanism to get out. If it tumbles too much, it can never go anywhere and can get stuck in a bad spot.”

In continuing research, the team plans to explore further the mechanism by which bacteria coordinate their flagella.

In the laboratory, E. coli chemotaxis—locomotion prompted by the presence of particular chemicals in the cell’s environment— is considered a model system for studying cellular decision-making. The signaling network inside the cell that causes it to run and tumble has been studied extensively, but it hasn’t been correlated directly to the cell’s swimming behavior.

“Understanding how the cells process information from their environment to pick alternate fates—like swimming vs. tumbling—is certainly a goal. How this decision-making feature evolved in a simple organism like E. coli could provide insights into decision-making in more complex organisms,” asserts Chemla.

The team's findings have been published in the online journal eLIFE.

link to article:

This work was supported by funding through an NSF Physics Frontier Center “Center for the Physics of Living Cells” Grant No. PHY-082265 (IG and YRC); NSF Grant No. PHY-1147498 (IG); NIH Grant No. R01 GM082837 (IG); NIH Grant No. R01 GM054365 (CVR); the Burroughs Wellcome Fund (YRC); the Welch Foundation Grant No Q-1759 (IG); and the Alfred P. Sloan Foundation (YRC). The conclusions presented are those of the scientists and not necessarily those of the funding agencies.