Comparisons of rbcL genes for the large subunit of ribulose-bisphosphate carboxylase from closely related C₃ and C₄ plant species

From National Research Council Canada

DOI	Resolve DOI: https://doi.org/10.1016/S0021-9258(19)40121-X
Author	Search for: Graham S. Hudson¹; Search for: John D. Mahon¹; Search for: Anderson, P. A.; Search for: Gibbs, M. J.; Search for: Badger, M. R.; Search for: Andrews, T. J.; Search for: Whitfeld, P. R.
Affiliation	National Research Council of Canada. NRC Plant Biotechnology Institute
Format	Text, Article
Abstract	Ribulosebisphosphate carboxylase/oxygenase from C₄ plants exhibits higher turnover rates and lower affinities for CO₂ than the enzyme from C₃ plants or C₃-C₄ intermediate species. This property is shown to be inherited maternally in reciprocal interspecific crosses between two Flaveria species, and thus must be specified by the chloroplast-encoded large subunits. To investigate the amino acid changes responsible, the chloroplast rbcL genes from three pairs of C₃ and C₄ species from three genera (Flaveria, Atriplex, and Neurachne) were cloned and sequenced. Comparisons of the predicted amino acid sequences from species of the same genus revealed a limited number of changes within each pair, ranging from three to six, of which only one (309Met (C₃) to Ile (C₄)) was consistently observed. This residue occurs in the loop connecting the carboxyl end of beta strand 5 with the amino end of alpha helix 5 in the alpha/beta barrel of the large subunit, and is close to the active site in a region which makes interdomain and intersubunit contacts. However, it is unlikely that a change of this residue alone is responsible for the alteration of kinetic properties. Nucleotide sequence comparisons of the rbcL genes showed no significant or consistent changes in the promoter and transcribed but nontranslated regions to suggest why rbcL is not expressed in C₄ leaf mesophyll cells. It is concluded that mutations in rbcL have led to an alteration of the kinetics but not the expression of ribulose-bisphosphate carboxylase.
Publication date	1990-01-15
Publisher	American Society for Biochemistry and Molecular Biology Elsevier
In	Journal of Biological Chemistry 265, no. 2 (15 January 1990): 808–814.
Language	English
Peer reviewed	Yes
Identifier	S002192581940121X
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Record identifier	2419866a-b443-49a9-b3b6-3a36c01abe11
Record created	2023-07-05
Record modified	2023-10-06

Date modified:: 2025-06-16