Oxygen-17 Appears Only in Protein in Water-Stressed Soybean Leaves Labeled by 17O2

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• 作者：Terry Gullion ; Tsyr-Yan Yu ; Manmilan Singh ; Gary J. Patti ; Gregory S. Potter ; Jacob Schaefer
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：August 11, 2010
• 年：2010
• 卷：132
• 期：31
• 页码：10802-10807
• 全文大小：220K
• 年卷期：v.132,no.31(August 11, 2010)
• ISSN：1520-5126

文摘

We have used a rotational-echo adiabatic-passage double-resonance ¹³C{¹⁷O} solid-state NMR experiment to prove that the glycine produced in the oxygenase reaction of ribulose bisphosphate carboxylase-oxygenase is incorporated exclusively into protein (or protein precursors) of intact, water-stressed soybean leaves exposed to ¹³CO₂ and ¹⁷O₂. The water stress increased stomatal resistance and decreased gas exchange so that the Calvin cycle in the leaf chloroplasts was no more than 35% ¹³C isotopically enriched. Labeled O₂ levels were sufficient, however, to increase the ¹⁷O isotopic concentration of oxygenase products 20-fold over the natural-abundance level of 0.04%. The observed direct incorporation of glycine into protein shows that water stress suppresses photorespiration in soybean leaves.