1MPQ

MALTOPORIN TREHALOSE COMPLEX

Summary for 1MPQ

• Entry DOI: 10.2210/pdb1mpq/pdb
• Related PRD ID: PRD_900006
• Descriptor: MALTOPORIN, alpha-D-glucopyranose-(1-1)-alpha-D-glucopyranose (2 entities in total)
• Functional Keywords: membrane protein, specific porin, beta barrel, sugar transport
• Biological source: Escherichia coli
• Cellular location: Cell outer membrane; Multi-pass membrane protein: P02943
• Total number of polymer chains: 3
• Total formula weight: 143304.25

Authors

Dutzler, R.,Schirmer, T. (deposition date: 1997-03-24, release date: 1998-03-25, Last modification date: 2024-10-09)

Primary citation

Wang, Y.F.,Dutzler, R.,Rizkallah, P.J.,Rosenbusch, J.P.,Schirmer, T.
Channel specificity: structural basis for sugar discrimination and differential flux rates in maltoporin.
J.Mol.Biol., 272:56-63, 1997

PubMed Abstract: Maltoporin (LamB) facilitates the diffusion of maltodextrins across the outer membrane of E. coli. The structural basis for the specificity of the channel is investigated by X-ray structure analysis of maltoporin in complex with the disaccharides sucrose, trehalose, and melibiose. The sucrose complex, determined to 2.4 A resolution, shows that the glucosyl moiety is partly inserted into the channel constriction, while the bulky fructosyl residue appears to be hindered to enter the constriction, thus interfering with its further translocation. One of the glucosyl moieties of trehalose is found in a similar position as the glucosyl moiety of sucrose, whereas melibiose appears disordered when bound to maltoporin. A comparison with the previously reported maltoporin-maltose complex sheds light on the basis for sugar discrimination, and explains the different permeation rates observed for the saccharides.

PubMed: 9299337
DOI: 10.1006/jmbi.1997.1224

Experimental method

X-RAY DIFFRACTION (3 Å)