PIGMENT/PROTEIN COMPLEXES OF THE INTERTIDAL ALGA CODIUM FRAGILE (SURINGAR) HARIOT

Abstract

Six pigment‐containing bands were isolated from Codium fragile thylakoids using sodium dodecyl sulphate/polyacrylamide gel electrophoresis. Two, designated CPla and CP1, were associated with Photosystem I and enriched in chlorophyll a and a‐carotene, and two light‐harvesting complexes (dimer LHCP1 and monomer LHCP2) were enriched in chlorophyll b, siphonoxanthin, siphonein and neoxanthin. A fifth pigment/protein (CPa) was not successfully characterized. Undissociated free pigment contained almost all the violaxanthin recovered from gel eluates and a high concentration of siphonoxanthin. Several high (100 ± 3.0 to 62 ± 7.7 kilodaltons) and two low molecular weight proteins (15.2 ± 1.2 to 16.5 plusmn; 1.2 and 18.0 kilodaltons) were thought to be associated with CPla and CP1. LHCP1 contained a protein of molecular weight 56 ± 24 kilodaltons and LHCP, a 29 kilodaltons protein, however the behaviour of these complexes after denaturation was particularly unusual in that on re‐electrophoresis the denatured monomer appeared to reassociate and proteins of 59, 56 and 28 kilodaltons were resolved. The composition of these pigment/protein complexes suggests that a large proportion of the pigments present in C. fragile chloroplasts function in a light‐harvesting capacity and this may be an adaptation to submarine photosynthesis. Copyright © 1983, Wiley Blackwell. All rights reserved