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Publication Abstract from PubMed

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.

Structural basis for sugar translocation through maltoporin channels at 3.1 A resolution.,Schirmer T, Keller TA, Wang YF, Rosenbusch JP Science. 1995 Jan 27;267(5197):512-4. PMID:7824948^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.