Protein methylation in pea chloroplasts. [Pisum sativum]

Journal Article · Sun Jul 01 00:00:00 EDT 1990 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.93.3.1235· OSTI ID:5945911

Niemi, K J; Adler, J; Selman, B R ^[1]

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1. Univ. of Wisconsin, Madison (USA)

The methylation of chloroplast proteins has been investigated by incubating intact pea (Pisum sativum) chloroplasts with ({sup 3}H-methyl)-S-adenosylmethionine. Incubation in the light increases the amount of methylation in both the thylakoid and stromal fractions. Numerous thylakoid proteins serve as substrates for the methyltransfer reactions. Three of these thylakoid proteins are methylated to a significantly greater extent in the light than in the dark. The primary stromal polypeptide methylated is the large subunit of ribulose bisphosphate carboxylase/oxygenase. One other stromal polypeptide is also methylated much more in the light than in the dark. Two distinct types of protein methylation occur. One methylinkage is stable to basic conditions whereas a second type is base labile. The base-stable linkage is indicative of N-methylation of amino acid residues while base-lability is suggestive of carboxymethylation of amino acid residues. Labeling in the light increases the percentage of methylation that is base labile in the thylakoid fraction while no difference is observed in the amount of base-labile methylations in light-labeled and dark-labeled stromal proteins. Also suggestive of carboxymethylation is the detection of volatile ({sup 3}H)methyl radioactivity which increases during the labeling period and is greater in chloroplasts labeled in the light as opposed to being labeled in the dark; this implies in vivo turnover of the ({sup 3}H)methyl group.

• OSTI ID: 5945911
• Journal Information: Plant Physiology; (USA), Vol. 93:3; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
14 SOLAR ENERGY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
RIBULOSE DIPHOSPHATE CARBOXYLASE
POST-TRANSLATION MODIFICATION
THYLAKOID MEMBRANE PROTEINS
CARBON-CARBON LYASES
CHLOROPLASTS
METHIONINE
METHYL TRANSFERASES
METHYLATION
PISUM
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINO ACIDS
CARBOXY-LYASES
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
DRUGS
ENZYMES
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
LEGUMINOSAE
LIPOTROPIC FACTORS
LYASES
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MEMBRANE PROTEINS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PLANTS
PROTEINS
TRANSFERASES
550201* - Biochemistry- Tracer Techniques
140505 - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
400500 - Photochemistry