LDRD Seminar Series: ‘Stabilization of Rubisco Activase for Enhanced Photosynthesis and Crop Yields’
Biophysicist Phani Raj Pokkuluri (BIO) will discuss his Laboratory-Directed Research and Development (LDRD) sponsored work at the LDRD Seminar Series presentation Tuesday, Jan. 30, 2018. “Stabilization of Rubisco Activase for Enhanced Photosynthesis and Crop Yields” begins at 12:30 p.m. in the Building 203 Auditorium. All are welcome to attend.
The speaker will introduce the essential but temperature-sensitive plant protein, Rubisco activase, and explain how its stability is improved by protein engineering, which could lead to higher photosynthetic yields.
Plants convert atmospheric CO2 with the help of sunlight into biomass. Plants grow poorly at temperatures even modestly higher than their optimum (5-10 degrees ºC) utilizing CO2 less efficiently. A study in Science reported that global warming is already adversely affecting harvest yields of food crops such as maize and wheat.
Rubisco is an enzyme that catalyzes the first step in carbon fixation utilizing atmospheric CO2. Rubisco activase is a chaperone protein that helps maintain Rubisco in the active form. However, Rubisco activase is a temperature-sensitive protein and itself becomes inactive easily.
Thermal instability of Rubisco activase is now well-established to be correlated with the inhibition of CO2 assimilation and net photosynthesis affecting plant growth. Our project aims to increase the temperature stability of Rubisco activase through rational protein engineering. The stabilization strategy was developed with the activase from food crop, soybean and later shown to be applicable to the bioenergy crop, miscanthus.
The stabilized version of the protein when incorporated into plants could help the carbon fixation process, resulting in higher plant growth and biomass yields. In light of the expected increase in global average temperatures this may be an important option for the crop security (both for food and bioenergy). In addition, it could help crops deal with unpredictable sudden heatwave events that are associated with global warming.
Raj Pokkuluri is a biophysicist in the Biosciences Division. He received a Ph.D. in chemistry from the University of British Columbia, Vancouver, Canada where his graduate research included small molecule crystallography and organic photochemical reaction selectivity in crystals versus solution phase. After receiving his Ph.D., he turned to structural biology, which has been his area of research ever since.
Arriving at Argonne as a postdoctoral fellow more than 23 years ago, just when the APS was setting out to produce world class X-rays for structural biology, Pokkuluri decided to take advantage of research possibilities here. His research interests are primarily in structural biology — understanding properties of proteins and how proteins carry out their functions from a structural perspective.
Pokkuluri has contributed to various projects funded by DOE’s BER, BES and NNSA, NIH, DARPA and LDRD. Research areas included various classes of proteins: carbohydrate and lignin degrading enzymes, immunoglobulins (Fab fragments, light chain domains), multiheme cytochromes containing up to 12 heme cofactors per protein chain, bacterial signal transduction proteins and photosynthetic reaction center, which is a large membrane protein complex composed of three protein chains and multiple cofactors.
His current focus, in collaboration with the Chemical Sciences and Engineering Division, is the creation of novel bio-hybrid materials for applications in solar fuels.