title: S-nitrosylated proteins of a medicinal CAM plant Kalanchoe pinnata- ribulose-1,5-bisphosphate carboxylase/oxygenase activity targeted for inhibition.
abstract: Nitric oxide (NO) is a signaling molecule that affects a myriad of processes in plants. However, the mechanistic details are limited. NO post-translationally modifies proteins by S-nitrosylation of cysteines. The soluble S-nitrosoproteome of a medicinal, crassulacean acid metabolism (CAM) plant, Kalanchoe pinnata, was purified using the biotin switch technique. Nineteen targets were identified by MALDI-TOF mass spectrometry, including proteins associated with carbon, nitrogen and sulfur metabolism, the cytoskeleton, stress and photosynthesis. Some were similar to those previously identified in Arabidopsis thaliana, but kinesin-like protein, glycolate oxidase, putative UDP glucose 4-epimerase and putative DNA topoisomerase II had not been identified as targets previously for any organism. In vitro and in vivo nitrosylation of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), one of the targets, was confirmed by immunoblotting. Rubisco plays a central role in photosynthesis, and the effect of S-nitrosylation on its enzymatic activity was determined using NaH14CO3. The NO-releasing compound S-nitrosoglutathione inhibited its activity in a dose-dependent manner suggesting Rubisco inactivation by nitrosylation for the first time.
authors.affiliation: Department of Botany, Plant Molecular Physiology and Biochemistry Laboratory, University of Delhi, India.
authors.forename: Jasmeet K
authors.initials: JK
authors.lastname: Abat
authors.forename: Autar K
authors.initials: AK
authors.lastname: Mattoo
authors.forename: Renu
authors.initials: R
authors.lastname: Deswal
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D001671:Biochemistry / Q000379:methods; D002244:Carbon / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry; D004250:DNA Topoisomerases, Type II / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000494:pharmacology; D031962:Kalanchoe / Q000378:metabolism*; D009584:Nitrogen / Q000737:chemistry; D010788:Photosynthesis; D010936:Plant Extracts / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D012273:Ribulose-Bisphosphate Carboxylase / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014534:UDPglucose 4-Epimerase / Q000737:chemistry
chemical_list: D004791:Enzyme Inhibitors; D010936:Plant Extracts; D010940:Plant Proteins; D002244:Carbon; D012273:Ribulose-Bisphosphate Carboxylase; D014534:UDPglucose 4-Epimerase; D004250:DNA Topoisomerases, Type II; D003545:Cysteine; D009584:Nitrogen