Blue-green mutant

Rivas, E.A., N.L. Kerber, A.A. Viale, and A.F. Garcia Isolation of a Basic Membrane Fraction Enriched in an Ornithine-Containing Lipid, from a Blue-green Mutant of Rhodospirillum rubrum. FEBS-Letters 11, 37 (1970). 

In contrast to the photosynthetic eukaryotes, photoprotection in cyanobacteria is not induced by the presence of a transthylakoid ApH or the excitation pressure on PSII. Instead, intense blue-green light (400-550 nm) induces a quenching of PSII fluorescence that is reversible in minutes even in the presence of translation inhibitors (El Bissati et al. 2000). Fluorescence spectra measurements and the study of the NPQ mechanism in phycobilisome- and PSII-mutants of the cyanobacterium Synechocystis PCC6803 indicate that this mechanism involves a specific decrease of the fluorescence emission of the phycobilisomes and a decrease of the energy transfer from the phycobilisomes to the RCs (Scott et al. 2006, Wilson et al. 2006). The site of the quenching appears to be the core of the phycobilisome (Scott et al. 2006, Wilson et al. 2006, Rakhimberdieva et al. 2007b). 

Figure 17.14 Model of evolved mutant from cephalosphorinase shuffling. The sequence of the most active cephalosporinase mutant was modeled using the crystal structure of the class C cephalosporinase from Enterobacter cloacae. The mutant and wild-type proteins were 63% identical. This chimeric protein contained portions from three of the starting genes, including Enterobacter (blue), Klebsiella (yellow), and Citrobacter (green), as well as 33 point mutations (red). (Courtesy of A. Crameri.)...

Figure 12.8 A. 2-PS reaction. B. Surface representations of the CHS (left) and 2-PS (right) active site cavities are shown. The catalytic cysteines (red), the three positions that convert CHS into 2-PS (green), and the substitution that does not affect product formation (blue) are highlighted. C. TLC analysis of CHS, 2-PS, and CHS mutant enzymes. The radiogram shows the radiolabeled products produced by incubation of each protein with [14C]malonyl-CoA and either p-coumaroyl-CoA (C) or acetyl-CoA (A). Numbering of mutants corresponds to CHS with 2-PS numbering in parenthesis. Positions of reaction products and their identities are indicated.

Figure 7 Sequence requirements of the leader peptides of nisin, mutacin II, lacticin 481, and lacticin 3147 as determined by site-directed mutagenesis. For nisin and mutacin II, mutants that still resulted in full processing of the prepeptides are shown in green, whereas mutants that resulted in abolished lantibiotic production are shown in orange. For lacticin 481, the mutants shown in green were good substrates in vitro for either the bifunctional synthetase LctM or the protease domain of LctT, whereas the mutants in orange were poor substrates. Conserved residues in the leader peptides of subgroups of lantibiotics are indicated in blue and red as described in Figure 6.

Figure 5 Consequences of point mutations in D1 (yellow) and CP43 (green). In the boxes, the first line (-E) indicates amino acids mutations that support photoautotrophic growth (light-E COp) and evolve Op. The second line (Op) indicates mutants that do not grow photoautotrophically but retain an initial Op evolution rate when grown heterotrophically (>5% vs. the wild-type strain). The third line (—) indicates lethal mutants that do not grow photoautotrophically, have no Op evolution activity, and in some cases no photooxidizable Mn. Amino acid color coding acidic (red), basic (blue), hydrophobic (brown)...

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