The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)

The ion coupling and organic substrate specificities of osmoregulatory transporter ProP in Escherichia coli.

Transporter ProP of Escherichia coli, a member of the major facilitator superfamily, mediates osmoprotective proline or glycine betaine accumulation by bacteria exposed to high osmolality environments. Morpholinopropane sulfonic acid, a common constituent of microbiological media, accumulates in osmoadapting E. coli cells but it is not osmoprotective and it did not influence proP transcription or ProP activity. The apparent K(m) for proline uptake via ProP increased with decreasing pH in the range 7.5-4. ProP-dependent proline uptake by de-energized bacteria was associated with alkalinization of the external medium. Thus ProP mediates cotransport of H(+) and zwitterionic proline and a transporter functional group with a pK(a) of 5-6 is implicated in catalysis. Exogenous proline or glycine betaine elicits K(+) release from osmoadapting E. coli cells and ProP activity is stimulated by exogenous K(+). However, uptake of proline or glycine betaine stimulated K(+) efflux from K(+)-loaded bacteria which expressed either ProP or alternative, osmoregulatory transporter ProU. This indicated that ProP was unlikely to mediate K(+) efflux. Zwitterions ectoine, pipecolate, proline betaine, N,N-dimethylglycine, carnitine and 1-carboxymethylpyridinium were identified as alternative ProP substrates. Choline, a cation and a structural analogue of glycine betaine, was a low affinity inhibitor but not a substrate of ProP.[1]


  1. The ion coupling and organic substrate specificities of osmoregulatory transporter ProP in Escherichia coli. MacMillan, S.V., Alexander, D.A., Culham, D.E., Kunte, H.J., Marshall, E.V., Rochon, D., Wood, J.M. Biochim. Biophys. Acta (1999) [Pubmed]
WikiGenes - Universities