Figure 2. Electron micrographs of particles isolated
from Prochlorococcus MIT 9313 separated on sucrose density
gradients. a, b, Band 2 (a) of cells grown in the presence of
iron (+Fe) containing both PSII particles (white arrow) and
naked PSI trimers (black arrow), and band 3 (b) of the sucrose
density gradient from cells grown in iron-deficient medium (-Fe)
containing the 18-mer Pcb–PSI supercomplex (black arrow).
The insert is the banding profile obtained by sucrose density
gradient centrifugation of thylakoid membranes solubilized with
1% beta-D-dodecyl maltoside isolated from Prochlorococcus
MIT 9313. Band 1 consists of free Pcb proteins. Scale bar, 50
nm.
