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1.A.23.4.3
Mechanosensative cation-selective channel with a conductance of 100 pS, YnaI (344aas; 4TMSs).  Protects against hypoosmotic shock (Edwards et al. 2012).  The structure has been solved by cryo-electron microscopy to a resolution of 13 A (Böttcher et al. 2015). While the cytosolic vestibule is structurally similar to that in MscS, additional density is seen in the transmembrane region, consistent with the presence of two additional TMSs predicted for YnaI. The location of this density suggests that the extra TMSs are tilted, which could induce local membrane curvature extending the tension-sensing paddles seen in MscS. Off-center lipid-accessible cavities are seen that resemble gaps between the sensor paddles in MscS. The conservation of the tapered shape and the cavities in YnaI suggest a mechanism similar to that of MscS (Böttcher et al. 2015). The voltage dependence of inactivation occurs independently of the positive charges of R46, R54, and R74 (Nomura et al. 2016). A 3.8 Å structure by cryoEM revealed a heptamer structural fold similar to previously studied MscS channels. The ion-selective filter is formed by seven hydrophobic methionines (Met158) in the transmembrane pore (Yu et al. 2017).

Accession Number:P0AEB5
Protein Name:MscS family inner membrane protein ynaI
Length:343
Molecular Weight:38755.00
Species:Escherichia coli (strain K12) [83333]
Number of TMSs:4
Location1 / Topology2 / Orientation3: Cell inner membrane1 / Multi-pass membrane protein2
Substrate small molecules, ions

Cross database links:

Genevestigator: P0AEB5
EchoBASE: EB3683
EcoGene: EG13924
eggNOG: COG0668
HEGENOM: HBG710405
Entrez Gene ID: 945898   
Pfam: PF00924   
KEGG: ecj:JW1323    eco:b1330   

Gene Ontology

GO:0016021 C:integral to membrane
GO:0005886 C:plasma membrane
GO:0055085 P:transmembrane transport

References (4)

[1] “A 570-kb DNA sequence of the Escherichia coli K-12 genome corresponding to the 28.0-40.1 min region on the linkage map.”  Aiba H.et.al.   9097039
[2] “The complete genome sequence of Escherichia coli K-12.”  Blattner F.R.et.al.   9278503
[3] “Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 and W3110.”  Hayashi K.et.al.   16738553
[4] “Global topology analysis of the Escherichia coli inner membrane proteome.”  Daley D.O.et.al.   15919996

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)

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MIAELFTNNA LNLVIIFGSC AALILMSFWF RRGNRKRKGF LFHAVQFLIY TIIISAVGSI 
61:	INYVIENYKL KFITPGVIDF ICTSLIAVIL TIKLFLLINQ FEKQQIKKGR DITSARIMSR 
121:	IIKITIIVVL VLLYGEHFGM SLSGLLTFGG IGGLAVGMAG KDILSNFFSG IMLYFDRPFS 
181:	IGDWIRSPDR NIEGTVAEIG WRITKITTFD NRPLYVPNSL FSSISVENPG RMTNRRITTT 
241:	IGLRYEDAAK VGVIVEAVRE MLKNHPAIDQ RQTLLVYFNQ FADSSLNIMV YCFTKTTVWA 
301:	EWLAAQQDVY LKIIDIVQSH GADFAFPSQT LYMDNITPPE QGR