1MAL

STRUCTURAL BASIS FOR SUGAR TRANSLOCATION THROUGH MALTOPORIN CHANNELS AT 3.1 ANGSTROMS RESOLUTION

Summary for 1MAL

• Entry DOI: 10.2210/pdb1mal/pdb
• Descriptor: MALTOPORIN (1 entity in total)
• Functional Keywords: outer membrane protein
• Biological source: Escherichia coli
• Cellular location: Cell outer membrane; Multi-pass membrane protein: P02943
• Total number of polymer chains: 3
• Total formula weight: 142277.36

Authors

Schirmer, T. (deposition date: 1994-11-24, release date: 1995-12-31, Last modification date: 2024-11-20)

Primary citation

Schirmer, T.,Keller, T.A.,Wang, Y.F.,Rosenbusch, J.P.
Structural basis for sugar translocation through maltoporin channels at 3.1 A resolution.
Science, 267:512-514, 1995

PubMed Abstract: Trimeric maltoporin (LamB protein) facilitates the diffusion of maltodextrins across the outer membrane of Gram-negative bacteria. The crystal structure of maltoporin from Escherichia coli, determined to a resolution of 3.1 angstroms, reveals an 18-stranded, antiparallel beta-barrel that forms the framework of the channel. Three inwardly folded loops contribute to a constriction about halfway through the channel. Six contingent aromatic residues line the channel and form a path from the vestibule to the periplasmic outlet. Soaking of a crystal with maltotriose revealed binding of the sugar to this hydrophobic track across the constriction, which suggests that maltose and linear oligosaccharides may be translocated across the membrane by guided diffusion along this path.

PubMed: 7824948

Experimental method

X-RAY DIFFRACTION (3.1 Å)