Delobel, Arnaud and Graciet, Emmanuelle and Andreescu, Simona and Gontero, Brigitte and Halgand, Frederic and Laprevote, Olivier (2005) Mass spectrometric analysis of the interactions between CP12, a chloroplast protein, and metal ions: a possible regulatory role within a PRK/GAPDH/CP12 complex. Rapid Communications in Mass Spectrometry, 19 (22). pp. 3379-3388. ISSN 1097-0231

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Abstract

The small chloroplast protein CP12 plays the role of a protein linker in the assembly process of a PRK/GAPDH/CP12 complex that is involved in CO2 assimilation in photosynthetic organisms. The redox state of CP12 regulates its role as a protein linker. Only the oxidized protein, with two disulfide bonds, is active in complex formation. Several observations indicating that CP12 might bind a metal ion led us to screen the binding of different metal ions on oxidized or reduced CP12 using non-covalent electrospray ionization mass spectrometry (ESI-MS) experiments. The oxidized protein bound specifically Cu2+ and Ni2+ (Kd of 26+/-1 microM and 11+/-1 microM, respectively); other cations such as Fe2+ and Zn2+ did not bind, while cations such as Cd2+ formed non-specific adducts to CP12. Similar results were obtained for metal ions on screening with the reduced CP12. Interestingly, the present results suggest that Cu2+ catalyzes the re-formation of the disulfide bonds of the reduced CP12, leading to recovery of the fully oxidized CP12 that is then able to bind a Cu2+ ion. Finally the high similarity between CP12 and copper chaperones from Arabidopsis thaliana, as judged by hydrophobic cluster analysis, provides additional evidence for the relevance of metal binding for the in vivo situation. The findings that CP12 is able to bind a metal ion, and that Cu2+ catalyzes the oxidation of the thiol groups of CP12, are new characteristics of this protein that may prove to be important in the regulation of the assembly process of the PRK/GAPDH/CP12 complex. Arnaud Delobel, Emmanuelle Graciet, Simona Andreescu, Brigitte Gontero, Frederic Halgand and Olivier Laprevote

Item Type:	Article
Keywords:	Mass spectrometric analysis; interactions; CP12; chloroplast protein; metal ions; PRK/GAPDH/CP12 complex;
Academic Unit:	Faculty of Science and Engineering > Biology
Item ID:	7430
Identification Number:	https://doi.org/10.1002/rcm.2192
Depositing User:	Emanuelle Graciet
Date Deposited:	06 Sep 2016 15:43
Journal or Publication Title:	Rapid Communications in Mass Spectrometry
Publisher:	Wiley
Refereed:	Yes
URI:	http://onlinelibrary.wiley.com
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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