1PV7

Crystal structure of lactose permease with TDG

Summary for 1PV7

• Entry DOI: 10.2210/pdb1pv7/pdb
• Related: 1PV6
• Related PRD ID: PRD_900027
• Descriptor: Lactose permease, beta-D-galactopyranose-(1-1)-1-thio-beta-D-galactopyranose (2 entities in total)
• Functional Keywords: transport, sugar transport, symport, membrane protein, transport protein
• Biological source: Escherichia coli
• Total number of polymer chains: 2
• Total formula weight: 93686.32

Authors

Abramson, J.,Smirnova, I.,Kasho, V.,Verner, G.,Kaback, H.R.,Iwata, S. (deposition date: 2003-06-26, release date: 2003-08-12, Last modification date: 2024-05-29)

Primary citation

Abramson, J.,Smirnova, I.,Kasho, V.,Verner, G.,Kaback, H.R.,Iwata, S.
Structure and mechanism of the lactose permease of Escherichia coli
SCIENCE, 301:610-615, 2003

PubMed Abstract: Membrane transport proteins that transduce free energy stored in electrochemical ion gradients into a concentration gradient are a major class of membrane proteins. We report the crystal structure at 3.5 angstroms of the Escherichia coli lactose permease, an intensively studied member of the major facilitator superfamily of transporters. The molecule is composed of N- and C-terminal domains, each with six transmembrane helices, symmetrically positioned within the permease. A large internal hydrophilic cavity open to the cytoplasmic side represents the inward-facing conformation of the transporter. The structure with a bound lactose homolog, beta-D-galactopyranosyl-1-thio-beta-D-galactopyranoside, reveals the sugar-binding site in the cavity, and residues that play major roles in substrate recognition and proton translocation are identified. We propose a possible mechanism for lactose/proton symport (co-transport) consistent with both the structure and a large body of experimental data.

PubMed: 12893935
DOI: 10.1126/science.1088196

Experimental method

X-RAY DIFFRACTION (3.6 Å)