Methanococcus jannaschiiGeneratesl-Proline by Cyclization ofl-Ornithine

Abstract

Cell extracts of Methanococcus jannaschii have been shown to readily convert l-ornithine tol-proline. This cyclization reaction proceeds with the loss of only the C-2 nitrogen, as has been documented for ornithine cyclodeaminase (EC 4.3.1.12). Since no gene homologous to that coding for ornithine cyclodeaminase is present in the genome of M. jannaschii, these results indicate that proline biosynthesis inM. jannaschii is accomplished by a previously unrecognized enzyme.