Documentation of auxotrophic mutation in blue-green bacteria: characterization of a tryptophan auxotroph in Agmenellum quadruplicatum.
A tryptophan-requiring auxotroph of Agmenellum quadruplicatum strain BG1, a species of blue-green bacteria, was isolated by means of a nitrosoguanidine-penicillin procedure. Its growth characteristics were determined, and the enzymological block was identified in the A activity of tryptophan synthetase. Starvation of the auxotroph for tryptophan resulted in the derepression of the synthesis of all five enzymes. The first four enzymes derepressed 2- to 3-fold, and tryptophan synthetase B derepressed 20-fold. In the parental prototroph, BG1, anthranilate synthetase was active in crude extracts with ammonia as the amino donor reactant, but not with glutamine.
D000878:Anthranilate Synthase / Q000378:metabolism; D002238:Carbohydrate Epimerases / Q000378:metabolism; D002262:Carboxy-Lyases / Q000378:metabolism; D002474:Cell-Free System; D000458:Cyanobacteria / Q000201:enzymology / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D004794:Enzyme Repression; D005994:Glycerophosphates; D009153:Mutagens; D009154:Mutation; D009604:Nitrosoguanidines; D010400:Penicillin G; D010430:Pentosyltransferases / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000378:metabolism*; D014367:Tryptophan Synthase / Q000378:metabolism; D062367:ortho-Aminobenzoates
D005994:Glycerophosphates; D009153:Mutagens; D009604:Nitrosoguanidines; D062367:ortho-Aminobenzoates; D014364:Tryptophan; D010430:Pentosyltransferases; D002262:Carboxy-Lyases; D000878:Anthranilate Synthase; D014367:Tryptophan Synthase; D002238:Carbohydrate Epimerases; D010400:Penicillin G