Purification and partial characterization of a glutamyl-tRNA synthetase from the unicellular green alga Scenedesmus obliquus, mutant C-2A?

Planta ◽  
1994 ◽  
Vol 192 (2) ◽  
Author(s):  
UteC. Vothknecht ◽  
Horst Senger ◽  
Dieter D�rnemann
Keyword(s):  
Green Alga ◽  
Scenedesmus Obliquus ◽  
Trna Synthetase ◽  
Partial Characterization ◽  
Unicellular Green Alga

Purification and Characterization of Cytochrome c6 from the Unicellular Green Alga Scenedesmus obliquus

1997 ◽  
Vol 52 (11-12) ◽  
pp. 740-746 ◽  
Author(s):  
Röbbe Wünschiers ◽  
Thomas Zinn ◽  
Dietmar Linder ◽  
Rüdiger Schulz
Keyword(s):  
Cytochrome C ◽  
Green Alga ◽  
Scenedesmus Obliquus ◽  
Terminal Sequence ◽  
Ammonium Sulfate Precipitation ◽  
Purification And Characterization ◽  
Unicellular Green Alga ◽  
Sds Page ◽  
Monoraphidium Braunii

Abstract Purification of a soluble cytochrome c6 from the unicellular green alga Scenedesmus obliquus by a simple and rapid method is described. The purification procedure includes ammonium sulfate precipitation and non-denaturating PAGE. The N-terminal sequence of the first 20 amino acids was determined and shows 85% similarity and 75% identity to the sequence of cytochrome c6 from the green alga Monoraphidium braunii. The ferrocyto-chrome shows typical UV/VIS absorption peaks at 552.9, 521.9 and 415.7 nm. The apparent molecular mass was estimated to be 12 kD a by SDS-PAGE. EPR-spectroscopy at 20K shows resonances indicative for two distinct low-spin heme forms.

Charging of Both, Plastidal tRNAgln and tRNAglu with Glutamate and Subsequent Amidation of the Misacylated tRNAgln by a Glutamyl-tRNA Amidotransferase in the Unicellular Green Alga Scenedesmus obliquus, Mutant C-2A'

1995 ◽  
Vol 50 (11-12) ◽  
pp. 789-795 ◽  
Author(s):  
U. C Vothknecht ◽  
D Dörnemann
Keyword(s):  
Green Alga ◽  
Cyanogen Bromide ◽  
Protein Biosynthesis ◽  
Scenedesmus Obliquus ◽  
Trna Synthetase ◽  
Higher Plant ◽  
Gram Positive Bacteria ◽  
Unicellular Green Alga ◽  
C5 Pathway ◽  
Sulfur Modification

Abstract , 1995 C5-Pathway, Glutamyl-tRNAglu-Synthetase (E.C.6.1.1.17), Misacylation of tR N A glu, Amidotransferase, Scenedesmus obliquus In a previous paper we described the purification of a glutamyl-tRNA synthetase from the unicellular green alga Scenedesmus obliquus, m utant C-2A'. We now dem onstrate that, firstly, this enzyme is capable of mischarging plastidal tR N A gln from barley with glutamate, as well as it regularly charges the plastidal tR N A glu from Scenedesmus. Secondly, we show that the mischarged glutamyl-tRNAgln is subsequently am idated by a glutamyl-tRNA am idotransfer­ ase to form the glutaminyl-tRNAglri required for plastidal protein biosynthesis. This phenom ­ enon could already be dem onstrated for higher plant chloroplasts, mitochondria, cyanobact­ eria and gram-positive bacteria, as far as investigated. As recently shown the applied glutamyl-tRNA synthetase from Scenedesmus is a plastidal enzyme. In this paper we prove by treatm ent with m onobromobim ane and cyanogen bromide that the "regular" substrate of the enzyme, tR N A glu from Scenedesmus, is a plastidal tRNA with the plastid-specific sulfur modification in the anticodon. In the case of cyanogen bromide treatm ent, a total inactivation of the tRNA was achieved, revealing the presence of a sulfur modification in the plastid-tRNA glu anticodon.

Isolation and Purification to Apparent Homogeneity of 4,5-Dioxovalerate Aminotransferase from Scenedesmus obliquus Mutant C-2 A′

1988 ◽  
Vol 43 (7-8) ◽  
pp. 563-571 ◽  
Author(s):  
A. Kah ◽  
D. Dörnemann ◽  
H. Senger
Keyword(s):  
Molecular Weight ◽  
Green Alga ◽  
Isoelectric Point ◽  
Pyridoxal Phosphate ◽  
Scenedesmus Obliquus ◽  
Ph Optimum ◽  
Isolation And Purification ◽  
Apparent Homogeneity ◽  
Unicellular Green Alga ◽  
Glyoxylate Aminotransferase

In the present paper the purification of a specific 4,5-dioxovalerate transaminase from pigment mutant C-2 A′ of the unicellular green alga Scenedesmus obliquus to apparent homogeneity is described. The newly isolated enzyme ʟ-glutamate: 4,5-dioxovalerate aminotransferase is not identical with ʟ-alanine: 4,5-dioxovalerate aminotransferase (EC 2.6.1.43) and ʟ-alanine: glyoxylate aminotransferase (EC 2.6.1.44). A procedure for the purification is described and the resulting homogeneous protein is characterized by its Kᴍ-values for oxo-substrates and amino donors, its pyridoxal phosphate requirement, reversability of the catalysis, pH-optimum, isoelectric point and its molecular weight.

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