ProP is a bacterial membrane protein that is a member of the major facilitator superfamily . It functions as an osmosensory and osmoregulatory transporter , responding to changes in osmotic pressure by importing compatible solutes such as proline or glycine betaine ;[ 1] most substrates for ProP are zwitterions .[ 2] The activity of ProP increases with osmotic pressure in cells and proteoliposomes.[ 3] [ 4] ProP is a symporter of hydrogen ions and compatible solutes, and is responsive to potassium concentrations.[ 2]
Activity of ProP has been associated with the ability of pathogenic E. coli to colonize the urinary tract .[ 3]
^ Culham DE, Lasby B, Marangoni AG, Milner JL, Steer BA, van Nues RW, Wood JM (January 1993). "Isolation and sequencing of Escherichia coli gene proP reveals unusual structural features of the osmoregulatory proline/betaine transporter, ProP". Journal of Molecular Biology . 229 (1): 268–76. doi :10.1006/jmbi.1993.1030 . PMID 8421314 .
^ a b MacMillan SV, Alexander DA, Culham DE, Kunte HJ, Marshall EV, Rochon D, Wood JM (August 1999). "The ion coupling and organic substrate specificities of osmoregulatory transporter ProP in Escherichia coli" . Biochimica et Biophysica Acta (BBA) - Biomembranes . 1420 (1–2): 30–44. doi :10.1016/s0005-2736(99)00085-1 . PMID 10446288 .
^ a b Culham DE, Dalgado C, Gyles CL, Mamelak D, MacLellan S, Wood JM (January 1998). "Osmoregulatory transporter ProP influences colonization of the urinary tract by Escherichia coli" . Microbiology . 144 ( Pt 1) (1): 91–102. doi :10.1099/00221287-144-1-91 . PMID 9467901 .
^ Racher KI, Voegele RT, Marshall EV, Culham DE, Wood JM, Jung H, Bacon M, Cairns MT, Ferguson SM, Liang WJ, Henderson PJ, White G, Hallett FR (February 1999). "Purification and reconstitution of an osmosensor: transporter ProP of Escherichia coli senses and responds to osmotic shifts". Biochemistry . 38 (6): 1676–84. doi :10.1021/bi981279n . PMID 10026245 .