A full-time Postdoctoral Research Associate position is available to study the phytochrome family of photoreceptors at the structural level to understand how they transition between their spectrally and conformationally distinct inactive Pr and active Pfr states. These photoreceptors pervade the microbial and plant worlds and control an assortment of processes important for growth, development, reproduction, motility, pigmentation and pathology. In plants, phytochromes are the dominant photoreceptors capable of triggering a number of critical developmental transitions, including seed germination, seedling growth, chloroplast development, shade avoidance, circadian rhythm entrainment, flowering time and senescence. Thus, understanding how phytochromes signal not only has interest at a basic science level but also with respect to crop improvement, the ecology of microbial communities, and disease prevention.
The goals of this newly-funded NIH project is to use an assortment of structure-based approaches to understand: (i) the early conformational events that occur during the milli-second transition between Pr and Pfr using both serial femtosecond crystallography with x-ray free-electron laser sources (XFEL) and temperature scanning crystallography; (ii) the structure of a phytochrome dimer in its Pr and Pfr states using an assortment of x-ray crystallography and cryo-EM approaches; (iii) how Pr and Pfr differ by structural and biochemical approaches, thus helping define the conformational changes that distinguish these two states; (iv) how various isoforms of plant phytochromes exploit their physico-chemical differences to enable perception of both light and temperature; and ultimately (v) how signaling by Pfr is transmitted to downstream signaling partners, be it microbial phytochromes that work in two-component kinase cascades, or plant phytochromes that employ reversible binding to a suite of PIF transcriptional repressors to drive photomorphogenesis. Importantly, all of the methodologies are in place to express spectrally-active phytochromes recombinantly and study them by cryo-EM and x-ray crystallography using conventiional synchrotron sources as well as by XFEL, using facilities both at Washington University and through various world-wide collaborators. Of particular import is our recent ability to generate diffraction-quality crystals of a phytochrome that retains its ability to transition between the inactive and active states while remaining locked in the crystal lattice. See recent papers by Burgie et al. (2015) PNAS; Burgie et al. (2016) Structure; Legris et al. (2016) Science; Fuller et al., (2017) Nat. Methods; Burgie et al. (2017) Sci. Rep.; and Huang et al., (2019) PNAS (in press), along with a general review on the topic by Burgie and Vierstra (2014) in Plant Cell for more background on the topic and information about experimental approaches. The project not only offers exciting science but also the ability to become proficient in modern 3D structure-based approaches.
Washington University in St. Louis is a center of excellence in all aspects of biology with a special emphasis on plant science, and includes modern facilities and instrumentation necessary for the work. In addition, both the Danforth Plant Science Center and companies such as Bayer Crop Sciences (formally Monsanto) are near by to make St. Louis an attractive place to do plant research with lots of technical expertise available. The nearby WashU Medical School offers expertise and collaborators in structural biology, including the newly established cryo-EM facility at the Washington University Center for Cellular Imaging (http://wucci.wustl.edu).
PRIMARY DUTIES AND RESPONSIBILITIES:
- Design, set up, and perform experiments related to understanding how phytochromes perceive light and signal at the atomic and molecular levels. Propose new directions and possible next steps. Coordinate efforts among concurrent experiments. Collect data and perform analysis. Ensure the continuity of our lab strains and supplies of recombinant photoreceptors.
- Prepare scientific data and manuscripts for publication.
- Help prepare grant proposals to support the research.
- Attend and present research progress at national and/or international meetings on the topics
- Possible need to travel to various synchrotron and XFEL x-ray sources for data collection.
- Promote discussion among laboratory members, implement changes to protocols. This will require adaptation and development of new protocols as the research progresses.
- Train and manage undergraduates and graduate students in conducting the research.
- Quality control: Help oversee all phytochrome-related projects and enforce the highest standards of quality and research conduct.
- Produce and maintain lab notebooks and insure periodic back up of all data.
- Maintain and organize the collection of stock cultures encoding various microbial and plant phytochromes and their signaling partners
- Maintain and organize the extensive x-ray crystallographic, XFEL and cryo-EM datasets generated from the work.
Required Qualifications: Ph.D in Biology.
- Ph.D in biochemistry, structural biology, molecular biology, or related fields.
- Excellent organizational and data management skills.
- Attention to detail.
- Proficiency with computers.
- Experience with various methods and programs to solve 3D structures is helpful.
- Experience with various assays describing protein/protein interactions and conformational changes, including hydrogen-deuterium exchange, is also advantageous.
- Experience with recombinant DNA methods, expressing proteins in various expression systems, and protein purification methodologies are helpful.
- If needed, successful candidate will be trained in advanced x-ray crystallography, XFEL and cryo-EM structural approaches.
- Ability to work well within a group, and to handle multiple concurrent assignments is essential.
Log in to jobs.wustl.edu to apply for position #43176.