PDBsum entry 1mpr

Membrane protein

PDB id: 1mpr

Contents

Protein chains

421 a.a. *

Metals

_CA

Waters ×456

* Residue conservation analysis

References listed in PDB file

Key reference

Title

Structure of maltoporin from salmonella typhimurium ligated with a nitrophenyl-Maltotrioside.

Authors

J.E.Meyer, M.Hofnung, G.E.Schulz.

Ref.

J Mol Biol, 1997, 266, 761-775. [DOI no: 10.1006/jmbi.1996.0823]

PubMed id

9102468

Abstract

The maltodextrin-specific (malto-)porin from Salmonella typhimurium has been crystallized. Its three-dimensional structure was determined at 2.4 A resolution (1 A = 0.1 nm). A comparison with the structure of the homologous porin from Escherichia coli as well as with the sequences of other related porins showed that there are regions of appreciable sequence and structure variability, despite close overall similarity. The maltoporin structure was analyzed with a bound nitrophenyl-maltotrioside as well as without ligand. Maltotrioside binding had a negligible effect on the polypeptide structure. It binds at the pore eyelet assuming a conformation close to the natural amylose helix.

Figure 6.
Figure 6. Stereo view of the interface around the molecular 3-fold axis. There is a water cluster in the interior and one calcium ion held by three aspartate residues at the external end of the interface (top). Because the respective residues are conserved, these features occur most likely also in the E. coli homologue.

Figure 8.
Figure 8. Superposition of C^α backbones of maltoporin from S. typhimurium (black) and its homologue from E. coli (red). Some loops at the external end of the β-barrel are labeled. There is no electron density at the tip of loop L6, indicating high mobility.

The above figures are reprinted by permission from Elsevier: J Mol Biol (1997, 266, 761-775) copyright 1997.