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Proline biosynthesis in Streptococcus thermophilus: characterization of the proBA operon and its products.

TitleProline biosynthesis in Streptococcus thermophilus: characterization of the proBA operon and its products.
Publication TypeJournal Article
Year of Publication1996
AuthorsLimauro, D, Falciatore, A, Basso, AL, Forlani, G, De Felice, M
JournalMicrobiology
Volume142 ( Pt 11)
Pagination3275-82
Date Published1996 Nov
ISSN1350-0872
KeywordsAldehyde Oxidoreductases, Amino Acid Sequence, Base Sequence, Chromosome Mapping, Cloning, Molecular, Culture Media, DNA, Bacterial, Genes, Bacterial, Glutamate-5-Semialdehyde Dehydrogenase, Molecular Sequence Data, Operon, Phosphotransferases (Carboxyl Group Acceptor), Proline, RNA, Bacterial, RNA, Messenger, Streptococcus
Abstract

The presence of proline in the medium was not essential for growth of Streptococcus thermophilus, indicating that there is a proline biosynthetic pathway in this organism. Genetic and biochemical analysis identified and characterized this pathway. Two genes, designated proB and proA, were cloned, sequenced and characterized. Biochemical analysis of the proB- and proA-encoded enzymes showed that the proline biosynthetic pathway of S. thermophilus is similar to the one previously described in Escherichia coli. The deduced amino acid sequence of a 2-408 kb DNA region containing the genes revealed the similarity of the S. thermophilus gene products to ProB and ProA of E. coli and Serratia marcescens, and to the corresponding N- and C-terminal domains of the bifunctional plant enzyme delta 1-pyrroline-5-carboxylate synthetase of Vigna aconitifolia. Northern blot analysis showed that the two genes in S. thermophilus are organized in a single operon with proB proximal and proA distal to the promoter; primer extension analysis indicated that proBA transcription is not under repressive control by exogenously supplied proline.

Alternate JournalMicrobiology (Reading, Engl.)
PubMed ID8969524