Three-dimensional Structure of the Sugar Symporter Melibiose Permease from Cryo-electron Microscopy
2005 (English)In: Journal of Structural Biology, ISSN 1047-8477, E-ISSN 1095-8657, Vol. 152, 76-83 p.Article in journal (Refereed) Published
Melibiose permease (MelB) of Escherichia coli is a secondary transporter that couples the uptake of melibiose and various other galactosides to symport of cations that can be Na+, Li+ or H+. MelB belongs to the glycoside-pentoside-hexuronide: cation symporter family of porters and is suggested to have 12 transmembrane helices. We have determined the three-dimensional structure of MelB at 10 angstrom resolution in the membrane plane with cryo-electron microscopy from two-dimensional crystals. The three-dimensional map shows a heart-shaped molecule composed of two domains with a large central cavity between them. The structure is constricted at one side of the membrane while it is open to the other. The overall molecular shape resembles those of lactose permease and glycerol-3-phosphate transporter. However, organization of helices in MOB seems less symmetrical than in these two members of the major facilitator superfamily.
Place, publisher, year, edition, pages
2005. Vol. 152, 76-83 p.
cryo-electron microscopy, membrane protein structure, sugar transporter, two-dimensional crystal
IdentifiersURN: urn:nbn:se:kth:diva-82969DOI: 10.1016/j.jsb.2005.07.003ISI: 000232572300007OAI: oai:DiVA.org:kth-82969DiVA: diva2:498630
QC 201203022012-02-122012-02-122012-03-02Bibliographically approved