EurekaMag
+ Translate
+ Most Popular
Gaucher's disease;thirty-two years experience at Siriraj Hospital
A study of Macrobathra Meyrick from China (Lepidoptera, Cosmopterigidae)
First occurrence in ores of tetragonal chalcocite
Effects of trace element nutrition on sleep patterns in adult women
N.Z. range management guidelines. 2. Design of grazing management systems for tussock country
A case of lipoma of the esophagus
A revision of world Acanthosomatidae (Heteroptera: Pentatomidae): keys to and descriptions of subfamilies, tribes and genera, with designation of types
Life history of the coronate scyphozoan Linuche unguiculata (Swartz, 1788)
Perceptual restoration of obliterated sounds
Mutagenicity studies on two chromium(III) coordination compounds
The formation of the skeleton. I. Growth of a long bone. 1st appearance of a center of calcification
Leucopenia and abnormal liver function in travellers on malaria chemoprophylaxis
The joint commission: four key root causes loom large in sentinel event data
Treatment of vitiligo with topical 15% lactic acid solution in combination with ultra violet-A
Behaviour of dairy cows within three hours after feed supply: I. Influence of housing type and time elapsing after feed supply
Observations of the propagation velocity and formation mechanism of burst fractures caused by gunshot
Management and control of patients with type 2 diabetes mellitus in Lebanon: results from the International Diabetes Management Practices Study (IDMPS)
The diet composition and nutritional knowledge of patients with anorexia nervosa
Physoporella croatica Herak, 1958 of the Slovak karst Anisian (Slovakia, the West Carpathians Mts.)
Bright lights, big noise. How effective are vehicle warning systems?
Ein Plesiosaurier-Rest mit Magensteinen aus mittlerem Lias von Quedlinburg
Incidence of Chlamydia trachomatis in patients with sterility
Monster soup: the microscope and Victorian fantasy
Preliminary tests with residual sprays against poultry lice
Duration of the life of plants in phylogeny

Topology of the porin MspA in the outer membrane of Mycobacterium smegmatis


Topology of the porin MspA in the outer membrane of Mycobacterium smegmatis



Journal of Biological Chemistry 281(9): 5908-5915



ISSN/ISBN: 0021-9258

PMID: 16352610

DOI: 10.1074/jbc.m511642200

MspA is the major porin of Mycobacterium smegmatis mediating the exchange of hydrophilic solutes across the outer membrane (OM). It is the prototype of a new family of octameric porins with a single central channel of 9.6 nm in length and consists of two hydrophobic beta-barrels of 3.7 nm in length and a more hydrophilic, globular rim domain. The length of the hydrophobic domain of MspA does not match the thicknesses of mycobacterial OMs of 5-12 nm as derived from electron micrographs. Further, the membrane topology of MspA is unknown as it is for any other mycobacterial OM protein. We used MspA as a molecular ruler to define the boundaries of the OM of M. smegmatis by surface labeling of single cysteine mutants. Seventeen mutants covered the surface of the rim domain and were biotinylated with a membrane-impermeable reagent. The label efficiencies in vitro were remarkably similar to the predicted accessibilities of the cysteines. By contrast, six of these mutants were protected from biotinylation in M. smegmatis cells. Tryptophan 21 defines a horizontal plane that dissects the surface-exposed versus the membrane-protected residues of MspA. The 8 phenylalanines at position 99 form a ring at the periplasmic end of the hydrophobic beta-barrel domain. These results indicated that (i) the membrane boundaries of MspA are defined by aromatic girdles as in porins of Gram-negative bacteria and (ii) loops and a 3.4-nm long part of the hydrophilic rim domain are embedded into the OM of M. smegmatis. This is the first report suggesting that elements other than hydrophobic alpha-helices or beta-sheets are integrated into a lipid membrane.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 013213913

Download citation: RISBibTeXText

Related references

The porin MspA from Mycobacterium smegmatis improves growth of Mycobacterium bovis BCG. International Journal of Medical Microbiology: Ijmm 294(4): 235-245, 2004

Cloning of the mspA gene encoding a porin from Mycobacterium smegmatis. Molecular Microbiology 33(5): 933-945, 1999

Functions of the periplasmic loop of the porin MspA from Mycobacterium smegmatis. Journal of Biological Chemistry 284(15): 10223-10231, 2009

Expression of the major porin gene mspA is regulated in Mycobacterium smegmatis. Journal of Bacteriology 189(3): 958-967, 2007

Allosteric Switching of Calmodulin in a Mycobacterium smegmatis porin A (MspA) Nanopore-Trap. Angewandte Chemie 60(44): 23863-23870, 2021

Characterization of nanostructured surfaces generated by reconstitution of the porin MspA from Mycobacterium smegmatis. Small 3(6): 1084-1097, 2007

Tailored Polymeric Membranes for Mycobacterium Smegmatis Porin A (MspA) Based Biosensors. Journal of Materials Chemistry. B 3(25): 5080-5086, 2015

Mapping Potential Engineering Sites of Mycobacterium smegmatis porin a (MspA) to Form a Nanoreactor. Acs Sensors 6(6): 2449-2456, 2021

Single Molecule Ratcheting Motion of Peptides in a Mycobacterium smegmatis Porin a (MspA) Nanopore. Nano Letters 21(15): 6703-6710, 2021

Translocation Behaviors of Synthetic Polyelectrolytes through Alpha-Hemolysin (α-HL) and Mycobacterium smegmatis Porin a (MspA) Nanopores. Journal of the Electrochemical Society 169(5), 2022

A Single-Molecule Observation of Dichloroaurate(I) Binding to an Engineered Mycobacterium smegmatis porin a (MspA) Nanopore. Analytical Chemistry 93(3): 1529-1536, 2021

Rapid and multiplex preparation of engineered Mycobacterium smegmatis porin A (MspA) nanopores for single molecule sensing and sequencing. Chemical Science 12(27): 9339-9346, 2021

Single molecule observation of hard-soft-acid-base (HSAB) interaction in engineered Mycobacterium smegmatis porin A (MspA) nanopores. Chemical Science 11(3): 879-887, 2019

Machine Learning Assisted Simultaneous Structural Profiling of Differently Charged Proteins in a Mycobacterium smegmatis Porin a (MspA) Electroosmotic Trap. Journal of the American Chemical Society 144(2): 757-768, 2022

Poly-N-Isopropylacrylamide/acrylic Acid Copolymers for the Generation of Nanostructures at Mica Surfaces and as Hydrophobic Host Systems for the Porin MspA from Mycobacterium smegmatis. Journal of Physical Chemistry. C Nanomaterials and Interfaces 113(37): 16485-16494, 2009