Disease relevance of ECs5093

• Insertion proQ220::Tn5 alters regulation of proline porter II, a transporter of proline and glycine betaine in Escherichia coli [1].
• BetS is a major glycine betaine/proline betaine transporter required for early osmotic adjustment in Sinorhizobium meliloti [2].

High impact information on ECs5093

• In whole cells, proline porter II activity was supported by glucose and by D-lactate in a strain defective for proline porters I and III and the F1F0-ATPase [3].
• Activation of proline porter II in whole cells by sucrose or NaCl was sustained over 30 min, whereas activation by glycerol was transient [3].
• However, their heat capacity functions, CD spectra, and temperature dependence of ellipticity at 222 nm were typical for peptides in the extended helical poly(L-proline) type II conformation (PPII), suggesting that they contain this type of regular structure [4].
• This osmotically inducible system allows the uptake of glycine betaine, proline, ectoine, and pipecolic acid and presents strong similarities in nucleotide sequence and protein function with the proline/betaine porter of Escherichia coli encoded by proP [5].
• Mutation pro-220::Tn5, which increases the resistance of Escherichia coli to 3,4-dehydroproline (M. E. Stalmach, S. Grothe, and J. M. Wood, J. Bacteriol. 156:481-486, 1983), is not linked to putP, proP, or proU [1].

Chemical compound and disease context of ECs5093

• Proline is accumulated in Escherichia coli via two active transport systems, proline porter I (PPI) and PPII [6].

Biological context of ECs5093

• The SH3Hck : PPIIhGAP fusion protein is useful for investigating SH3: PPII helix interactions, for studying concepts in protein folding and design, and may represent a protein structural motif that is widely distributed in nature [7].

Associations of ECs5093 with chemical compounds

• Proline porter II was activated by NaCl and sucrose with a half-time of approximately 1 min in both whole cells and membrane vesicles [3].
• 3,4-Dehydroproline-resistant mutants derived from a putP putA mutant lack proline porter II [8].
• PPII, which has a lower affinity for proline than PPI, was induced by tryptophan-limited growth [6].
• The dependence of that inhibition on glycine betaine concentration was similar when PPII was uninduced, induced or activated by osmotic stress, or induced by amino acid limited growth [9].

References