Subategory:

Mutants

Description:

Using standard methods of directed mutagenesis and chloroplast transformation of rbcLΔ/rbcS1-SSAT pf2 mt+ (MUT-4927), 12 substitutions (V149Q, G168P, V221C, C256F, K258R, I265V, I282H, L326I, M349L, M375L, A398S, and C399V) together in the Rubisco large subunit were created. This mutant (also named AG265/SSAT) represents one of 15 "associated groups" of amino acids that differ between Chlamydomonas and land plants. It was created to investigate phylogenetic differences that influence Rubisco catalysis. The 12 substitutions in the large subunit must be complemented by the presence of the Arabidopsis small subunit (SSAT) to produce a functional Rubisco holoenzyme. The mutant strain requires 5% CO₂ in air for photosynthetic growth, and has a decrease in Rubisco holoenzyme stability. It has been maintained with acetate medium in darkness to prevent selection for secondary mutations that may improve Rubisco function.

Species:

Chlamydomonas

Locus:

rbcL, RBCS1

Chromosome:

Chloroplast,2

Phenotype:

Requires elevated CO₂ for photosynthetic growth