The structure of a mycobacterial outer-membrane channel

Science. 2004 Feb 20;303(5661):1189-92. doi: 10.1126/science.1094114.

Abstract

Mycobacteria have low-permeability outer membranes that render them resistant to most antibiotics. Hydrophilic nutrients can enter by way of transmembrane-channel proteins called porins. An x-ray analysis of the main porin from Mycobacterium smegmatis, MspA, revealed a homooctameric goblet-like conformation with a single central channel. This is the first structure of a mycobacterial outer-membrane protein. No structure-related protein was found in the Protein Data Bank. MspA contains two consecutive beta barrels with nonpolar outer surfaces that form a ribbon around the porin, which is too narrow to fit the thickness of the mycobacterial outer membrane in contemporary models.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arginine / chemistry
  • Cell Membrane Permeability
  • Cloning, Molecular
  • Crystallization
  • Crystallography, X-Ray
  • Electric Conductivity
  • Escherichia coli / genetics
  • Hydrogen Bonding
  • Hydrophobic and Hydrophilic Interactions
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation
  • Mycobacterium smegmatis / chemistry*
  • Mycobacterium smegmatis / metabolism
  • Porins / chemistry*
  • Porins / genetics
  • Porins / metabolism
  • Protein Conformation
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Recombinant Proteins / chemistry

Substances

  • Porins
  • Recombinant Proteins
  • mspA protein, Mycobacterium smegmatis
  • Arginine

Associated data

  • PDB/1UUN