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Protein

Porin MspA

Gene

mspA

Organism
Mycobacterium smegmatis (strain ATCC 700084 / mc(2)155)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

The major porin in this organism, forms a water-filled channel which favors the permeation of cations, amino acids, iron Fe3+ and less efficiently phosphate. Does not transport Fe-ExoMS, the predominant siderophore. Plays a role in transport of beta-lactamase and hydrophilic fluoroquinolone antibiotics such as norfloxacin as well as chloramphenicol. There are about 2400 porins in wild-type, 800 in an mspA deletion and 150 in a double mspA-mspC deletion. Different conductance values with maxima at 2.3 and 4.6 nanosiemens might be caused by a simultaneous reconstitution of MspA channels into the membrane or by the existence of different MspA conformations.5 Publications

GO - Molecular functioni

GO - Biological processi

Keywordsi

Molecular functionPorin
Biological processIon transport, Iron transport, Transport
LigandIron

Protein family/group databases

TCDBi1.B.24.1.1. the mycobacterial porin (mbp) family.

Names & Taxonomyi

Protein namesi
Recommended name:
Porin MspA
Gene namesi
Name:mspA
Ordered Locus Names:MSMEG_0965, MSMEI_0939
OrganismiMycobacterium smegmatis (strain ATCC 700084 / mc(2)155)
Taxonomic identifieri246196 [NCBI]
Taxonomic lineageiBacteriaActinobacteriaCorynebacterialesMycobacteriaceaeMycobacterium
Proteomesi
  • UP000006158 Componenti: Chromosome
  • UP000000757 Componenti: Chromosome

Subcellular locationi

GO - Cellular componenti

Keywords - Cellular componenti

Cell outer membrane, Cell wall, Membrane, Secreted

Pathology & Biotechi

Disruption phenotypei

Single deletion has decreased permeability to the antibiotic cephaloridine (9-fold), glucose (4-fold), serine, phosphate and iron Fe3+. Growth rates are wild-type, due to the other Msp-type porins. A double mspA-mspC deletion takes up less cephaloridine, glucose, serine and phosphate than the single mspA deletion and grows slower than wt or single mspA deletion. A triple mspA-mspC-mspD deletion grows even slower and has reduced Fe3+ transport compared to wild-type.5 Publications

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi96G → R: Increases yield of ordered crystals. 1 Publication1

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Signal peptidei1 – 271 PublicationAdd BLAST27
ChainiPRO_500006428528 – 211Porin MspAAdd BLAST184

Expressioni

Inductioni

Constitutively expressed.1 Publication

Interactioni

Subunit structurei

Forms very stable octamers. Isolated as a 100 kDa complex that can be reduced to monomers upon boiling in 80% dimethyl sulfoxide for 15 minutes. Structures show a goblet with the wide end on the exterior of the outer membrane and a central channel. It is not known if mixed oligomers of MspA with other Msp subunits form in vivo.2 Publications

Protein-protein interaction databases

STRINGi246196.MSMEG_0965.

Structurei

Secondary structure

1211
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Beta strandi29 – 36Combined sources8
Beta strandi42 – 55Combined sources14
Beta strandi65 – 79Combined sources15
Helixi82 – 84Combined sources3
Beta strandi86 – 96Combined sources11
Beta strandi98 – 110Combined sources13
Beta strandi115 – 119Combined sources5
Turni124 – 129Combined sources6
Beta strandi130 – 132Combined sources3
Beta strandi139 – 148Combined sources10
Beta strandi153 – 178Combined sources26
Beta strandi180 – 183Combined sources4
Beta strandi186 – 195Combined sources10
Beta strandi200 – 204Combined sources5

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1UUNX-ray2.50A/B28-211[»]
2V9UX-ray2.59A/B/C/D/E/F/G/H28-211[»]
ProteinModelPortaliA0QR29.
SMRiA0QR29.
ModBaseiSearch...
MobiDBiSearch...

Family & Domainsi

Domaini

The rim domain (28-96 and 152-211) is accessible from the external milieu and is partially embedded in the outer membrane. The stem domain (131-148) is inaccessible from the outside and embedded in the outer membrane, while loop 6 (121-127) is thought to be in the periplasm.1 Publication

Sequence similaritiesi

Keywords - Domaini

Signal, Transmembrane, Transmembrane beta strand

Phylogenomic databases

HOGENOMiHOG000074392.
OMAiTEARENM.
OrthoDBiPOG091H09AR.

Family and domain databases

InterProiView protein in InterPro
IPR016183. Leukocidin/porin.
IPR015286. Porin_fam_mycobact-type.
PfamiView protein in Pfam
PF09203. MspA. 1 hit.
SUPFAMiSSF56959. SSF56959. 1 hit.

Sequencei

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

A0QR29-1 [UniParc]FASTAAdd to basket

« Hide

        10         20         30         40         50
MKAISRVLIA MVAAIAALFT STGTSHAGLD NELSLVDGQD RTLTVQQWDT
60 70 80 90 100
FLNGVFPLDR NRLTREWFHS GRAKYIVAGP GADEFEGTLE LGYQIGFPWS
110 120 130 140 150
LGVGINFSYT TPNILIDDGD ITAPPFGLNS VITPNLFPGV SISADLGNGP
160 170 180 190 200
GIQEVATFSV DVSGAEGGVA VSNAHGTVTG AAGGVLLRPF ARLIASTGDS
210
VTTYGEPWNM N
Length:211
Mass (Da):22,118
Last modified:January 9, 2007 - v1
Checksum:iB4DEC5639904487A
GO

Mass spectrometryi

Molecular mass is 19406±2 Da from positions 28 - 211. Determined by MALDI. 1 Publication

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
AJ001442 Genomic DNA. Translation: CAB56052.1.
CP000480 Genomic DNA. Translation: ABK74363.1.
CP001663 Genomic DNA. Translation: AFP37419.1.
RefSeqiWP_011727317.1. NZ_CP009494.1.
YP_885367.1. NC_008596.1.

Genome annotation databases

EnsemblBacteriaiABK74363; ABK74363; MSMEG_0965.
AFP37419; AFP37419; MSMEI_0939.
GeneIDi4533718.
KEGGimsb:LJ00_04780.
msg:MSMEI_0939.
msm:MSMEG_0965.
PATRICifig|246196.19.peg.953.

Similar proteinsi

Entry informationi

Entry nameiMSPA_MYCS2
AccessioniPrimary (citable) accession number: A0QR29
Secondary accession number(s): I7G4H6, Q9RLP7
Entry historyiIntegrated into UniProtKB/Swiss-Prot: March 21, 2012
Last sequence update: January 9, 2007
Last modified: June 7, 2017
This is version 74 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  2. SIMILARITY comments
    Index of protein domains and families