RT Journal Article SR Electronic(1) A1 Limauro, Danila A1 Falciatore, Angela A1 Basso, Anna L. A1 Forlani, Giuseppe A1 De Felice, MaurilioYR 1996 T1 Proline biosynthesis in Streptococcus thermophilus: characterization of the proBA operon and its products JF Microbiology, VO 142 IS 11 SP 3275 OP 3282 DO https://doi.org/10.1099/13500872-142-11-3275 PB Microbiology Society, SN 1465-2080, AB 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 Δ1-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., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/13500872-142-11-3275