tailieunhanh - Báo cáo khóa học: Protein assembly of photosystem II and accumulation of subcomplexes in the absence of low molecular mass subunits PsbL and PsbJ

The protein assembly and stability of photosystem II (PSII) (sub)complexes were studied inmature leaves of four plastid mutants of tobacco (Nicotiana tabacumL), each havingone of thepsbEFLJoperon genes inactivated. In the absence of psbL, no PSII core dimers or PSII–light harvesting complex (LHCII) supercomplexes were formed, and the assembly of CP43 into PSII core monomers was extremely labile. The assembly of CP43 intoPSII coremonomers was found to be necessary for the assembly of PsbO on the lumenal side of PSII. . | Eur. J. Biochem. 271 96-107 2004 FEBS 2003 doi Protein assembly of photosystem II and accumulation of subcomplexes in the absence of low molecular mass subunits PsbL and PsbJ Marjaana Suorsa1 Ralph E. Regel2 Virpi Paakkarinen1 Natalia Battchikova1 Reinhold G. Herrmann2 and Eva-Mari Aro1 1 Department of Biology Plant Physiology and Molecular Biology University of Turku Finland 2Botanisches Institute der Ludwig-Maximilians Universitat Miinchen Germany The protein assembly and stability of photosystem II PSII sub complexes were studied in mature leaves of four plastid mutants of tobacco Nicotiana tabacum L each having one of the psbEFLJ operon genes inactivated. In the absence of psbL no PSII core dimers or PSII-light harvesting complex LHCII supercomplexes were formed and the assembly of CP43 into PSII core monomers was extremely labile. The assembly of CP43 into PSII core monomers was found to be necessary for the assembly of PsbO on the lumenal side of PSII. The two other oxygen-evolving complex OEC proteins PsbP and PsbQ were completely lacking in DpsbL. In the absence of psbJ both intact PSII core monomers and PSII core dimers harboringthe PsbO protein were formed whereas the LHCII antenna remained detached from the PSII dimers as demonstrated by 77 K fluorescence measurements and by the lack of PSII-LHCII supercomplexes. The DpsbJmutant was characterized by a deficiency of PsbQ and a complete lack of PsbP. Thus both the PsbL and PsbJ subunits of PSII are essential for proper assembly of the OEC. The absence of psbE and psbF resulted in a complete absence of all central PSII core and OEC proteins. In contrast very young vigorously expanding leaves of all psb-EFLJ operon mutants accumulated at least traces of D2 CP43 and the OEC proteins PsbO and PsbQ implying developmental control of the expression of the PSII core and OEC proteins. Despite severe problems in PSII assembly the thylakoid membrane complexes other than PSII were .