Event Title

Regulation of the Rubisco activase isoforms in Zea mays through Mg2+ and concentration under temperature constraints

Advisor(s)

Dr. Sarah Stainbrook; Washington University of St. Louis

Discipline

Biology

Start Date

21-4-2021 9:30 AM

End Date

21-4-2021 9:45 AM

Abstract

Over the next century, higher temperatures perpetuated by global warming influence crop production in climate-change-induced yield loss. The enzyme Rubisco activase (RCA) is a key protein that removes inhibitors from Rubisco, the enzyme responsible for the carbon dioxide fixation during photosynthesis. High temperatures impede RCA’s efficiency and in turn slow down the net rate of photosynthesis. In maize, two isoforms of RCA are regulated differently in regards to light.

Our research examined the differences between the α and β isoforms in maize and how they were affected by heat, concentration of RCA, and magnesium (Mg2+) activation.

We harvested leaf tissue via grinding in liquid nitrogen, purified Rubisco and RCA purified, and confirmed by Coomassie stain and Western blot. We also cloned each isoform in Escherichia coli and expressed them for purification. All tests compared RCA purified from maize vs each isoform expressed from E. coli. We measured RCA activity using ATPase and 3PGA production, coupled to NADH absorption for a spectrophotometric readout.

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Apr 21st, 9:30 AM Apr 21st, 9:45 AM

Regulation of the Rubisco activase isoforms in Zea mays through Mg2+ and concentration under temperature constraints

Over the next century, higher temperatures perpetuated by global warming influence crop production in climate-change-induced yield loss. The enzyme Rubisco activase (RCA) is a key protein that removes inhibitors from Rubisco, the enzyme responsible for the carbon dioxide fixation during photosynthesis. High temperatures impede RCA’s efficiency and in turn slow down the net rate of photosynthesis. In maize, two isoforms of RCA are regulated differently in regards to light.

Our research examined the differences between the α and β isoforms in maize and how they were affected by heat, concentration of RCA, and magnesium (Mg2+) activation.

We harvested leaf tissue via grinding in liquid nitrogen, purified Rubisco and RCA purified, and confirmed by Coomassie stain and Western blot. We also cloned each isoform in Escherichia coli and expressed them for purification. All tests compared RCA purified from maize vs each isoform expressed from E. coli. We measured RCA activity using ATPase and 3PGA production, coupled to NADH absorption for a spectrophotometric readout.