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2.A.1.6.4
(Proline/glycine-betaine):(H+/Na+) symporter, ProP (also transports taurine, ectoine, pipecolate, proline-betaine, N,N-dimethylglycine, carnitine, and 1-carboxymethyl-pyridinium) (subject to osmotic activation). Transmembrane helix I and periplasmic loop 1 are involved in osmosensing and osmoprotectant transport (Keates et al., 2010). ProP detects the increase in cytoplasmic cation concentration associated with osmotically induced cell dehydration and mediates osmolyte uptake into bacteria (Ozturk et al. 2020). ProP is a 12-TMS protein with an α-helical, cytoplasmic C-terminal domain (CTD) linked to TMS XII. The CTD helix associates with the anionic membrane surface to lock ProP in an inactive conformation. The release of the CTD may activate ProP. Molecular dynamics simulations showed specific intrapeptide salt bridges forming when the CTD associated with the membrane. The salt bridge Lys447-Asp455 weakened CTD-lipid interactions at 0.25 M KCl, and gradual stiffening of the membrane with increasing salinity was obseerved. Thus, salt cations may affect CTD release and activate ProP by increasing the order of membrane phospholipids (Ozturk et al. 2020).

Accession Number:P0C0L7
Protein Name:Proline/betaine transporter ProP aka B4111
Length:500
Molecular Weight:54846.00
Species:Escherichia coli [83333]
Number of TMSs:12
Location1 / Topology2 / Orientation3: Cell inner membrane1 / Multi-pass membrane protein2
Substrate Glycine betaine, H+, Na+, Proline

Cross database links:

Genevestigator: P0C0L7
EchoBASE: EB1569
EcoGene: EG11612
eggNOG: COG0477
HEGENOM: HBG757988
RefSeq: AP_004612.1    NP_418535.1   
Entrez Gene ID: 948626   
Pfam: PF08946    PF00083   
BioCyc: EcoCyc:PROP-MONOMER    ECOL168927:B4111-MONOMER   
KEGG: ecj:JW4072    eco:b4111   

Gene Ontology

GO:0016021 C:integral to membrane
GO:0005886 C:plasma membrane
GO:0015295 F:solute:hydrogen symporter activity
GO:0015292 F:uniporter activity
GO:0042538 P:hyperosmotic salinity response
GO:0015824 P:proline transport
GO:0055085 P:transmembrane transport

References (6)

[1] “Isolation and sequencing of Escherichia coli gene proP reveals unusual structural features of the osmoregulatory proline/betaine transporter, ProP.”  Culham D.E.et.al.   8421314
[2] “Analysis of the Escherichia coli genome VI: DNA sequence of the region from 92.8 through 100 minutes.”  Burland V.D.et.al.   7610040
[3] “The complete genome sequence of Escherichia coli K-12.”  Blattner F.R.et.al.   9278503
[4] “Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110.”  Hayashi K.et.al.   16738553
[5] “Global topology analysis of the Escherichia coli inner membrane proteome.”  Daley D.O.et.al.   15919996
[6] “Solution structure of the C-terminal antiparallel coiled-coil domain from Escherichia coli osmosensor ProP.”  Zoetewey D.L.et.al.   14643666
Structure:
1R48   1Y8S     

External Searches:

  • Search: DB with
  • BLAST ExPASy (Swiss Institute of Bioinformatics (SIB) BLAST)
  • CDD Search (Conserved Domain Database)
  • Search COGs (Clusters of Orthologous Groups of proteins)
  • 2° Structure (Network Protein Sequence Analysis)

Analyze:

Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MLKRKKVKPI TLRDVTIIDD GKLRKAITAA SLGNAMEWFD FGVYGFVAYA LGKVFFPGAD 
61:	PSVQMVAALA TFSVPFLIRP LGGLFFGMLG DKYGRQKILA ITIVIMSIST FCIGLIPSYD 
121:	TIGIWAPILL LICKMAQGFS VGGEYTGASI FVAEYSPDRK RGFMGSWLDF GSIAGFVLGA 
181:	GVVVLISTIV GEANFLDWGW RIPFFIALPL GIIGLYLRHA LEETPAFQQH VDKLEQGDRE 
241:	GLQDGPKVSF KEIATKYWRS LLTCIGLVIA TNVTYYMLLT YMPSYLSHNL HYSEDHGVLI 
301:	IIAIMIGMLF VQPVMGLLSD RFGRRPFVLL GSVALFVLAI PAFILINSNV IGLIFAGLLM 
361:	LAVILNCFTG VMASTLPAMF PTHIRYSALA AAFNISVLVA GLTPTLAAWL VESSQNLMMP 
421:	AYYLMVVAVV GLITGVTMKE TANRPLKGAT PAASDIQEAK EILVEHYDNI EQKIDDIDHE 
481:	IADLQAKRTR LVQQHPRIDE