Open AccessThe transport and catabolism of l ‐proline by cowpea Rhizobium NGR 234
Author(s) -
Glenn A.R.,
Holliday S.,
Dilworth M.J.
Publication year - 1991
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1991.tb04900.x
Subject(s) - proline , biochemistry , proline dehydrogenase , extracellular , catabolism , intracellular , amino acid , biology , valine , rhizobium , chemistry , metabolism , gene
Cowpea Rhizobium NGR234 grows with a mean generation time of 3.5 h on l ‐proline; intracellular catabolism via proline oxidase and pyrroline 5‐carboxylate dehydrogenase is induced by proline. In contrast, cells have some capacity to take up proline whatever the growth medium. Uptake of proline is active and transmembrane gradients of approximately 290‐fold can be generated. The proline transporter(s) appear to carry a range of amino acids and intracellular [ 14 C]proline can be exchanged with extracellular valine or histidine or isoleucine but not glutamate. Snake bean bacteroids are unable to transport or catabolize l ‐proline, consistent with the lack of detectable proline in snakebean nodule cytosol. In this symbiosis at least, proline is not an important carbon source for bacteroids.