Role of plastid transglutaminase in LHCII polyamination and thylakoid electron and proton flow
Ioannidis, Nikolaos E. (Centre de Recerca en Agrigenòmica)
Lopera Ortega, Oriol (Centre de Recerca en Agrigenòmica)
Santos, Mireya (Centre de Recerca en Agrigenòmica)
Torné, Josep M. (Centre de Recerca en Agrigenòmica)
Kotzabasis, Kiriakos (University of Crete. Department of Biology)

Date:	2012
Abstract:	Transglutaminases function as biological glues in animal cells, plant cells and microbes. In energy producing organelles such as chloroplasts the presence of transglutaminases was recently confirmed. Furthermore, a plastidial transglutaminase has been cloned from maize and the first plants overexpressing tgz are available (Nicotiana tabacum TGZ OE). Our hypothesis is that the overexpression of plastidal transglutaminase will alter photosynthesis via increased polyamination of the antenna of photosystem II. We have used standard analytical tools to separate the antenna from photosystem II in wild type and modified plants, 6 specific antibodies against LHCbs to confirm their presence and sensitive HPLC method to quantify the polyamination level of these proteins. We report that bound spermidine and spermine were significantly increased (∼80%) in overexpressors. Moreover, we used recent advances in in vivo probing to study simultaneously the proton and electron circuit of thylakoids. Under physiological conditions overexpressors show a 3-fold higher sensitivity of the antenna down regulation loop (qE) to the elicitor (luminal protons) which is estimated as the ΔpH component of thylakoidal proton motive force. In addition, photosystem (hyper-PSIIα) with an exceptionally high antenna (large absorption cross section), accumulate in transglutaminase over expressers doubling the rate constant of light energy utilization (Kα) and promoting thylakoid membrane stacking. Polyamination of antenna proteins is a previously unrecognized mechanism for the modulation of the size (antenna absorption cross section) and sensitivity of photosystem II to down regulation. Future research will reveal which peptides and which residues of the antenna are responsible for such effects.
Grants:	Ministerio de Educación y Ciencia BFU2009-08575 Ministerio de Ciencia e Innovación CSD2007-00036 Ministerio de Educación y Ciencia BFU2006-15115-01/BMC
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Published in:	PloS one, Vol. 7, issue 7 (Jul. 2012) , e41979, ISSN 1932-6203

DOI: 10.1371/journal.pone.0041979
PMID: 22870182

14 p, 2.0 MB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CRAG (Centre for Research in Agricultural Genomics)
Articles > Research articles
Articles > Published articles