Open AccessX‐ray crystallographic and biochemical characterizations of a mutant photosystem II complex from Thermosynechococcus vulcanus with the psbTc gene inactivated by an insertion mutation
Author(s) -
Henmi Takahiro,
Iwai Masako,
Ikeuchi Masahiko,
Kawakami Keisuke,
Shen JianRen,
Kamiya Nobuo
Publication year - 2008
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s0909049508002458
Subject(s) - mutant , dimer , photosystem ii , protein subunit , chemistry , mutation , crystallography , biology , stereochemistry , gene , microbiology and biotechnology , photosynthesis , biochemistry , organic chemistry
The crystal structure of a photosystem II (PSII) dimer from Thermosynechococcus vulcanus with its psbTc gene inactivated by insertion mutation of an antibiotic cassette in a site in the C‐terminal region was analyzed at 3.8 Å resolution. In the crystal structure of the mutant PSII, the transmembrane helix of PsbTc remains, whereas the C‐terminal loop of PsbTc has disappeared. In addition, the PsbM subunit, which seemed to be lost in a PsbTc‐deletion mutant PSII of T. elongatus , is still present. The deletion of the C‐terminal loop of PsbTc in the mutant PSII was verified by mass spectrometry. Thus, the insertion mutation of psbTc eliminated only the C‐terminal loop of this subunit. Nevertheless, some features of the mutant PSII, namely a destabilization of the dimeric form and a slight decrease of the oxygen‐evolving activity, were observed in the mutant, indicating that the C‐terminal loop of PsbTc functions to maintain the stability of the PSII dimer and the activity of oxygen evolution.