Experimental basis of the data

The accumulation of the core subunits of Photosystem I (PSI), Photosystem II (PSII), the chloroplast ATPase, and the cytochrome b6f complex (cyt b6f) were assayed by probing western blots containing equal amounts of total leaf proteins with a cocktail of antisera that detect one subunit of each complex. Typically, the cocktail included antisera to AtpA, PsbA, PsaD, and PetD. Generally, the abundance of these subunits reflects the abundance of the other closely associated subunits in the same complex.

LHCP is the major light harvesting chlorophyll a/b binding protein associated with PSII. It's abundance and the abundance of Rubisco (RbcL) were assessed by examination of Ponceau S stained blots of total leaf extracts.

OE16 and OE23 are found in the thlakoid lumen and are translocated across the chloroplast membrane via the tat/delta pH mechanism. We assay these proteins to probe the integrity of the tat/delta pH targeting pathway. Defects in this pathway are associated with a reduced level of mature OE23 and OE16 and an increase in the level of their stromal precursor forms (iOE23 and iOE16).

Proteins were quantified by comparison with a dilution series of wild-type samples.

The data are presented here at low resolution to simplify searches for particular patterns of protein losses and because the precise % loss of a particular complex can vary with growth conditions. Please contact us if you would like to know more detail about individual mutants.

The size and abundance of chloroplast mRNAs encoding affected proteins are currently being assayed. These data will be added to the web site as they are produced.

Abbreviations used

LHCP	Light Harvesting Chlorophyll a/b binding Protein
RbcL	The large subunit of Rubisco (Ribulose Bisphosphate Carboxylase/Oxygenase)
ATPase	The chloroplast ATPase
Cyt bf6	Cytochrome b6f complex
PSI	Photosystem I
PSII	Photosystem II
PC	Plastocyanin: a small (10.5 kDa) Cu-containing protein which acts as an electron carrier between the cytochrome b6f and photosystem I
iPC	precursor to Plastocyanin
OEC 16 & 23	The 16 and 23 kDa subunits of the Oxygen Evolving complex
iOEC 16 & 23	precursors to the 16 and 23kDa subunits of the Oxygen Evolving complex