Abstract
The crystal structure of the maltodextrin-specific porin from Salmonella typhimurium ligated with a maltotrioside at the pore eyelet is known at 2.4 A resolution. The three glucose units assume a conformation close to the natural amylose helix. The pore eyelet fits exactly the cross-section of a maltooligosaccharide chain and thus functions as a constraining orifice. The oligomer permeates the membrane by screwing along the amylose helix through this orifice. Because each glucose glides along the given helix, its interactions can be sampled at any point along the pathway. The interactions are mostly hydrogen bonds, but also contacts to aromatic rings at one side of the pore. We have derived the energy profile of a gliding maltooligosaccharide by following formation and breakage of hydrogen bonds and by assessing the saccharide-aromatics interactions from a statistical analysis of saccharide binding sites in proteins. The resulting profile indicates smooth permeation despite extensive hydrogen bonding at the orifice.
Full Text
The Full Text of this article is available as a PDF (1.8 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Benz R., Schmid A., Nakae T., Vos-Scheperkeuter G. H. Pore formation by LamB of Escherichia coli in lipid bilayer membranes. J Bacteriol. 1986 Mar;165(3):978–986. doi: 10.1128/jb.165.3.978-986.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chakrabarti P., Samanta U. CH/pi interaction in the packing of the adenine ring in protein structures. J Mol Biol. 1995 Aug 4;251(1):9–14. doi: 10.1006/jmbi.1995.0411. [DOI] [PubMed] [Google Scholar]
- Connolly M. L. The molecular surface package. J Mol Graph. 1993 Jun;11(2):139–141. doi: 10.1016/0263-7855(93)87010-3. [DOI] [PubMed] [Google Scholar]
- Cowan S. W., Schirmer T., Rummel G., Steiert M., Ghosh R., Pauptit R. A., Jansonius J. N., Rosenbusch J. P. Crystal structures explain functional properties of two E. coli porins. Nature. 1992 Aug 27;358(6389):727–733. doi: 10.1038/358727a0. [DOI] [PubMed] [Google Scholar]
- Goldsmith E., Sprang S., Fletterick R. Structure of maltoheptaose by difference Fourier methods and a model for glycogen. J Mol Biol. 1982 Apr 5;156(2):411–427. doi: 10.1016/0022-2836(82)90336-9. [DOI] [PubMed] [Google Scholar]
- Kreusch A., Schulz G. E. Refined structure of the porin from Rhodopseudomonas blastica. Comparison with the porin from Rhodobacter capsulatus. J Mol Biol. 1994 Nov 11;243(5):891–905. doi: 10.1006/jmbi.1994.1690. [DOI] [PubMed] [Google Scholar]
- Nikaido H. Porins and specific diffusion channels in bacterial outer membranes. J Biol Chem. 1994 Feb 11;269(6):3905–3908. [PubMed] [Google Scholar]
- 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. 1995 Jan 27;267(5197):512–514. doi: 10.1126/science.7824948. [DOI] [PubMed] [Google Scholar]
- Schulz G. E. Bacterial porins: structure and function. Curr Opin Cell Biol. 1993 Aug;5(4):701–707. doi: 10.1016/0955-0674(93)90143-e. [DOI] [PubMed] [Google Scholar]
- Schülein K., Benz R. LamB (maltoporin) of Salmonella typhimurium: isolation, purification and comparison of sugar binding with LamB of Escherichia coli. Mol Microbiol. 1990 Apr;4(4):625–632. doi: 10.1111/j.1365-2958.1990.tb00631.x. [DOI] [PubMed] [Google Scholar]
- Thirion J. P., Hofnung M. On some genetic aspects of phage lambda resistance in E. coli K12. Genetics. 1972 Jun;71(2):207–216. doi: 10.1093/genetics/71.2.207. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Weiss M. S., Abele U., Weckesser J., Welte W., Schiltz E., Schulz G. E. Molecular architecture and electrostatic properties of a bacterial porin. Science. 1991 Dec 13;254(5038):1627–1630. doi: 10.1126/science.1721242. [DOI] [PubMed] [Google Scholar]
- Weiss M. S., Wacker T., Weckesser J., Welte W., Schulz G. E. The three-dimensional structure of porin from Rhodobacter capsulatus at 3 A resolution. FEBS Lett. 1990 Jul 16;267(2):268–272. doi: 10.1016/0014-5793(90)80942-c. [DOI] [PubMed] [Google Scholar]