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Title: Turnover of thylakoid membrane proteins during senescence of primary bean leaves. [Phaseolus vulgaris]

Pulse-labelling of primary bean leaves (Phaseolus vulgaris) with /sup 35/S-methionine has revealed differential changes in the rates at which proteins in thylakoid membranes are synthesized during senescence. In particular, synthesis of the 32 Kd herbicide-binding protein remains highly active throughout senescence, whereas turnover of the ..cap alpha.. and ..beta.. subunits of ATPase and of the LHCP declines. During a 24-h pulse chase experiment with unlabelled methionine, only the 32 KD protein showed evidence of degradation. Degradation of the 32 Kd unit and, to a lesser extent, of other thylakoid proteins was also observed when the membranes were aged in vitro. The latter process resembled that observed in vivo in that it was light dependent, sensitive to DCMU, and it was inhibited by spermine and Ca/sup 2 +/, both of which alter membrane fluidity. Collectively, these observations suggest that in vitro aging of thylakoid membranes is a useful model system for studying the characteristics of the thylakoid protein degradation.
Authors:
; ; ;
Publication Date:
OSTI Identifier:
5506213
Resource Type:
Conference
Resource Relation:
Journal Name: Plant Physiol.; (United States); Journal Volume: 80:4; Conference: Annual meeting of the American Society of Plant Physiologists, Baton Rouge, LA, USA, 8-12 Jun 1986
Research Org:
Univ. of Waterloo, Ontario
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; PHASEOLUS; PLANT GROWTH; BIOLOGICAL MODELS; PROTEINS; BIOCHEMICAL REACTION KINETICS; AGE DEPENDENCE; LABELLED COMPOUNDS; LEAVES; METHIONINE; PHOTOSYNTHETIC MEMBRANES; PLANT CELLS; PROTEOLYSIS; SULFUR 35; TRACER TECHNIQUES; AMINO ACIDS; BACTERIA; BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; CARBOXYLIC ACIDS; CHEMICAL REACTIONS; DAYS LIVING RADIOISOTOPES; DECOMPOSITION; DRUGS; EVEN-ODD NUCLEI; GROWTH; ISOTOPE APPLICATIONS; ISOTOPES; KINETICS; LEGUMINOSAE; LIGHT NUCLEI; LIPOTROPIC FACTORS; MEMBRANES; MICROORGANISMS; NUCLEI; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC SULFUR COMPOUNDS; PLANTS; RADIOISOTOPES; REACTION KINETICS; RHIZOBIUM; SULFUR ISOTOPES 551001* -- Physiological Systems-- Tracer Techniques