PT  - JOURNAL ARTICLE
AU  - Glick, Richard E.
AU  - Zilinskas, Barbara A.
TI  - Role of the Colorless Polypeptides in Phycobilisome Reconstitution from Separated Phycobiliproteins
AID  - 10.1104/pp.69.5.991
DP  - 1982 May 01
TA  - Plant Physiology
PG  - 991--997
VI  - 69
IP  - 5
4099  - http://www.plantphysiol.org/content/69/5/991.short
4100  - http://www.plantphysiol.org/content/69/5/991.full
SO  - Plant Physiol.1982 May 01; 69
AB  - A phycoerythrin (PE) and phycocyanin (PC) mixture was separated from allophycocyanin on calcium phosphate chromatography from completely dissociated phycobilisomes of the blue-green alga, Nostoc sp. After dialysis of the PE-PC mixture in 0.75 m potassium phosphate, pH 7, which allows reassociation of the dissociated pigment-proteins, complexes of PE and PC in a 2:1 m ratio (PE/PC complex) as well as complexes predominantly of PC (PC/PE complex) were then separated by sedimentation on linear sucrose gradients. These complexes resemble the rods of intact phycobilisomes and transfer energy efficiently from PE to PC. They contain the Group II colorless polypeptides described by Tandeau de Marsac and Cohen-Bazire (1977 Proc Natl Acad Sci USA 74: 1635 61639). Phycobilisomes can be reconstituted by combining the allophycocyanin pool with (a) the PE-PC mixture, (b) the PE/PC complex, or (c) the PC/PE complex. Successful reconstitution is measured by absorption, fluorescence, circular dichroism, and electron microscopy. The major requirement for reconstitution is the 29-kilodalton colorless polypeptide. In its absence, no phycobilisomes are formed. It is the only colorless polypeptide common to both the PE/PC complex and the PC/PE complex, and appears to be the polypeptide responsible for rod attachment to the allophycocyanin. In addition, high phosphate concentrations and 20°C temperatures are needed for reconstitution.