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Title: Topography of thylakoid membranes: In situ localization of photosystems I and II. [Porphyridium cruentum]

Abstract

The organization of the photosynthetic membrane structure is being studied in the red alga Porphyridium cruentum. Excitation energy transfer between the photosystems, which occurs readily in red algae and cyanobacteria, requires a close spatial relationship between the photosystems. The authors initial efforts have focused on the in situ labelling of PSI and PSII, two of four major protein complexes in thylakoids. Stoichiometries of PSI and PSII in P. cruentum are readily affected by light spectral quality. Cultures grown under continuous red light contain nearly five times as many A{sub A}'s per P{sub 700} as cells grown under green light. Thylakoids were isolated from cells grown under red or green light, and rinsed exhaustively to remove stromal proteins and phycobilisomes. These membranes were spread on electron microscope grids and immunolabelled with affinity-purified IgG antibodies to PSI and PSII. Gold particles were directly coupled to the antibodies of PSI (10 nm Au) and PSII (15nm Au). The labelling results are consistent with the Q{sub A} and P{sub 700} determinations. The density of PSII is greater in membranes from red light cells relative to green light cells, while the PSI density is greater in green light cells. The photosystems appear to be uniformlymore » distributed over the thylakoid membranes. Double labelling experiments indicate that PSI and PSII can occur in close proximity with a distance of less than 20 nm. Such proximity increases the possibility of excitation energy transfer between PSI and PSII.« less

Authors:
; ;  [1]
  1. Univ. of Maryland, College Park (United States)
Publication Date:
OSTI Identifier:
5401938
Report Number(s):
CONF-9107184-
Journal ID: ISSN 0079-2241; CODEN: PPYSA
Resource Type:
Conference
Journal Name:
Plant Physiology, Supplement; (United States)
Additional Journal Information:
Journal Volume: 96:1; Conference: Annual meeting of the American Society of Plant Physiology, Albuquerque, NM (United States), 28 Jul - 1 Aug 1991; Journal ID: ISSN 0079-2241
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; ALGAE; PHYSIOLOGY; PHOTOSYNTHETIC MEMBRANES; CELL CULTURES; CHARGE EXCHANGE; IMMUNOASSAY; THYLAKOID MEMBRANE PROTEINS; BIOASSAY; MEMBRANE PROTEINS; MEMBRANES; ORGANIC COMPOUNDS; PLANTS; PROTEINS; 551000* - Physiological Systems

Citation Formats

Gantt, E, Mustardy, L, and Cunningham, Jr, F X. Topography of thylakoid membranes: In situ localization of photosystems I and II. [Porphyridium cruentum]. United States: N. p., 1991. Web.
Gantt, E, Mustardy, L, & Cunningham, Jr, F X. Topography of thylakoid membranes: In situ localization of photosystems I and II. [Porphyridium cruentum]. United States.
Gantt, E, Mustardy, L, and Cunningham, Jr, F X. Wed . "Topography of thylakoid membranes: In situ localization of photosystems I and II. [Porphyridium cruentum]". United States.
@article{osti_5401938,
title = {Topography of thylakoid membranes: In situ localization of photosystems I and II. [Porphyridium cruentum]},
author = {Gantt, E and Mustardy, L and Cunningham, Jr, F X},
abstractNote = {The organization of the photosynthetic membrane structure is being studied in the red alga Porphyridium cruentum. Excitation energy transfer between the photosystems, which occurs readily in red algae and cyanobacteria, requires a close spatial relationship between the photosystems. The authors initial efforts have focused on the in situ labelling of PSI and PSII, two of four major protein complexes in thylakoids. Stoichiometries of PSI and PSII in P. cruentum are readily affected by light spectral quality. Cultures grown under continuous red light contain nearly five times as many A{sub A}'s per P{sub 700} as cells grown under green light. Thylakoids were isolated from cells grown under red or green light, and rinsed exhaustively to remove stromal proteins and phycobilisomes. These membranes were spread on electron microscope grids and immunolabelled with affinity-purified IgG antibodies to PSI and PSII. Gold particles were directly coupled to the antibodies of PSI (10 nm Au) and PSII (15nm Au). The labelling results are consistent with the Q{sub A} and P{sub 700} determinations. The density of PSII is greater in membranes from red light cells relative to green light cells, while the PSI density is greater in green light cells. The photosystems appear to be uniformly distributed over the thylakoid membranes. Double labelling experiments indicate that PSI and PSII can occur in close proximity with a distance of less than 20 nm. Such proximity increases the possibility of excitation energy transfer between PSI and PSII.},
doi = {},
journal = {Plant Physiology, Supplement; (United States)},
issn = {0079-2241},
number = ,
volume = 96:1,
place = {United States},
year = {1991},
month = {5}
}

Conference:
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