CHLOROPHYLL-PROTEINS OF THYLAKOIDS FROM WILD-TYPE AND MUTANTS OF BARLEY (HORDEUM-VULGARE-L)

A sodium dodecyl sulphate-polyacrylamide gel electrophoresis system is described that resolves wild-type barley thylakoid components into ten chlorophyll-containing bands, plus free chlorophyll. Many of these bands have been characterised with respect to their absorption spectra and polypeptide composition. The identity and probable function of eight bands were established by comparison of the wild-type pattern with those of isolated light-harvesting chlorophyll a/b-protein complex and a number of nuclear gene mutants of barley. It was found that the mutant chlorina-f2, which lacks chlorophyll b, contains only three chlorophyll a-proteins designated Chla-P1, Chla-P2 and Chl3-P3 according to a new system of nomenclature proposed in this paper. Chla-P1 contains the reaction centre of photosystem I (P700) and with the aid of the mutant viridis-m 29, Chla-P3 was deduced to be the most likely site of the reaction centre (P680) of photosystem II. Two chlorophyll a/b-proteins were found, which differed in their a/b ratios and which are thought to play a role in light-harvesting or light-focusing. These were designated Chla/b-P1 and Chla/b-P2, the latter being found in multimeric complexes designated Chla/b-P2*, Chla/b-P2** and Chla/b-P2***, in order of increasing apparent molecular weight. In addition to these eight bands, there were two chlorophyll-containing bands in the wild-type pattern that were not Chla/b-P2 complexes and which were called Chl-P bands until further characterised. © 1979 Carlsberg Laboratory.