Preliminary study on electron crystallography of 27 kD LHC-II complex from cucumber

Cucumber ( Cucumis sativus L.) LHC-II complex, which consists of only one subunit (27 kD); was isolated and purified. 2-D crystallization was performed by batch method. The crystal is 0.7 mum x 1.0 mum, and diffracts to 30 Angstrom. The projection map of the negatively stained two-dimensional crystal of LHC-II complex shows that the crystal has p3 symmetry, lattice constant 15.4 nm x 15.4 nm, which is different from the LHC- II of spinach (Spinacia oleracea L.) and pea (Pisum satium L.). A continuous tomographic tilt series, containing 12 projections from the two-dimensional crystal was subjected to 3-D reconstruction. The 3-D model represents that LHC- II complex consists of 6 monomers. These trimer and dimer interactions build up the six-member ring.