ORGANIZATION OF PHOTOSYSTEM-I POLYPEPTIDES - A STRUCTURAL INTERACTION BETWEEN THE PSAD AND PSAL SUBUNITS

被引:32
作者
XU, Q [1 ]
ARMBRUST, TS [1 ]
GUIKEMA, JA [1 ]
CHITNIS, PR [1 ]
机构
[1] KANSAS STATE UNIV AGR & APPL SCI, DIV BIOL, MANHATTAN, KS 66506 USA
关键词
D O I
10.1104/pp.106.3.1057
中图分类号
Q94 [植物学];
学科分类号
071001 ;
摘要
The wild-type, PsaD-less, and PsaL-less strains of the cyanobacterium Synechocystis sp. PCC 6803 were used to study subunit interactions in photosystem I (PSI). When the membranes of a PsaD-less strain were solubilized with Triton X-100 and PSI was purified using ion-exchange chromatography and sucrose-gradient ultracentrifugation, the PsaL subunit was substantially removed from the core of PSI, whereas other subunits, such as PsaE and PsaF, were quantitatively retained during purification. When the wild-type PSI was exposed to increasing concentrations of Nal, the PsaE, PsaD, and PsaC subunits were gradually removed, whereas PsaF, PsaL, PsaK, and PsaJ resisted removal by up to 3 M Nal. The absence of PsaL enhanced the accessibility of PsaD to removal by Nal. Treatment of the wild-type PSI complexes with glutaraldehyde at 4 degrees C resulted in a 29-kD cross-linked product between PsaD and PsaL. The formation of such cross-linked species was independent of PSI concentrations, suggesting an intracomplex cross-linking between PsaD and PsaL. Taken together, these results demonstrate a structural interaction between PsaD and PsaL that plays a role in their association with the PSI core.
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页码:1057 / 1063
页数:7
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