Channel specificity: structural basis for sugar discrimination and differential flux rates in maltoporin.Wang, Y.F., Dutzler, R., Rizkallah, P.J., Rosenbusch, J.P., Schirmer, T.
(1997) J.Mol.Biol. 272: 56-63
- PubMed: 9299337
- DOI: 10.1006/jmbi.1997.1224
- Primary Citation of Related Structures:
- PubMed Abstract:
- Crystal Structures of Various Maltooligosaccharides Bound to Maltoporin Reveal a Specific Sugar Translocation Pathway
Dutzler, R.,Wang, Y.F.,Rizkallah, P.,Rosenbusch, J.P.,Schirmer, T.
(1996) Structure 4: 127
- Structural Basis for Sugar Translocation Through Maltoporin Channels at 3.1 A Resolution
Schirmer, T.,Keller, T.A.,Wang, Y.F.,Rosenbusch, J.P.
(1995) Science 267: 512
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 suc ...
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.
Department of Microbiology, Biozentrum, University of Basel, Basel, CH-4056, Switzerland.