Multiple Genes for the Last Step of Proline Biosynthesis in Bacillus subtilis

Abstract
The complete Bacillus subtilis genome contains four genes ( proG, proH, proI, and comER ) with the potential to encode Δ 1 -pyrroline-5-carboxylate reductase, a proline biosynthetic enzyme. Simultaneous defects in three of these genes ( proG, proH, and proI ) were required to confer proline auxotrophy, indicating that the products of these genes are mostly interchangeable with respect to the last step in proline biosynthesis.