ISSN:
1432-072X
Keywords:
Rhodopseudomonas palustris
;
Photosynthetic Bacteria
;
Aspartate Family Amino Acids
;
Metabolic Regulation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The four amino acids of the “aspartate family” (l-lysine, l-methionine, l-threonine, and l-isoleucine) are produced in bacteria by a branched biosynthetic pathway. Regulation of synthesis of early common intermediates and of carbon flow through distal branches of the pathway requires operation of a number of subtle feedback controls, which are integrated so as to ensure “balanced” synthesis of the several end products. Earlier studies with nonsulfur purple photosynthetic bacteria were instrumental in revealing the existence of alternative regulatory schemes, and in this communication we report on the control pattern of a representative of this physiological group not previously investigated, Rhodopseudomonas palustris. The results obtained from study of the properties of four “key” regulatory enzymes of the aspartate family pathway (β-aspartokinase, homoserine dehydrogenase, homoserine kinase, and threonine deaminase) and of the effects of exogenous amino acids (i. e., the end products) on growth of the bacterium indicate that the control schema in Rps. palustris differs substantially from the schemes described for other Rhodopseudomonas species, but resembles the regulatory pattern observed in Rhodospirillum rubrum.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00455938
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