Biotic Stress/Applied Plant Bio

Abstract

CS-8-3 - Thylakoid Biogenesis in Cyanobacteria Monitored by Stable-Isotope Labeling of Proteins and Lipids

Sunday, July 15
3:58 PM - 4:18 PM

The biosynthesis of thylakoid membranes in cyanobacteria remains unresolved. The chlL deletion strain of Synechocystis, which is unable to synthesize chlorophyll in darkness but can make chlorophyll in the light, virtually lacks thylakoids in darkness but synthesizes them rapidly in the light, indicating that chlorophyll availability is a key factor associated with thylakoid biosynthesis. We grew the strain lacking chlL under light-activated heterotrophic growth (LAHG; 15 min of light per day and dark otherwise) conditions and followed synthesis of new components by means of labeling with 13C-glucose. In LAHG-grown cells lacking chlL, lipids were present at levels comparable to those in cells grown in continuous light but many of the proteins associated with the photosystems were greatly depleted. Upon 13C-labeling upon illumination of the LAHG-grown chlL deletion strain, chlorophyll-binding proteins were preferentially labeled, in line with rapid synthesis of chlorophyll molecules, whereas some other proteins were not rapidly labeled. Indeed, correlated biosynthesis of chlorophyll and chlorophyll-binding proteins is in line with the notion that chlorophyll needs to be bound to carotenoid-containing proteins to be harmless to the cell. These labeling experiments provide important insights into cellular storage and new biosynthesis of thylakoid components, and provide a kinetic perspective on thylakoid biogenesis in cyanobacteria. This work was funded by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy through Grant DE-FG02-11ER15543.

Co-Authors

Shuqin Li, Dr – School of Life Sciences, Arizona State University Daniel Brune, Dr – Arizona State University Vicki Moore, Dr – Arizona State University

Wim Vermaas

Foundation Professor
Arizona State University

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CS-8-3 - Thylakoid Biogenesis in Cyanobacteria Monitored by Stable-Isotope Labeling of Proteins and Lipids



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