3RLB

Crystal structure at 2.0 A of the S-component for thiamin from an ECF-type ABC transporter

Summary for 3RLB

• Entry DOI: 10.2210/pdb3rlb/pdb
• Descriptor: ThiT, nonyl beta-D-glucopyranoside, 3-(4-AMINO-2-METHYL-PYRIMIDIN-5-YLMETHYL)-5-(2-HYDROXY-ETHYL)-4-METHYL-THIAZOL-3-IUM, ... (4 entities in total)
• Functional Keywords: s-component, ecf transporter, abc transporter, substrate-binding domain, membrane, thiamine-binding protein
• Biological source: Lactococcus lactis subsp. cremoris
• Total number of polymer chains: 2
• Total formula weight: 46364.01

Authors

Erkens, G.B.,Berntsson, R.P.-A.,Fulyani, F.,Majsnerowska, M.,Vujicic-Zagar, A.,ter Beek, J.,Poolman, B.,Slotboom, D.J. (deposition date: 2011-04-19, release date: 2011-06-29, Last modification date: 2024-02-28)

Primary citation

Erkens, G.B.,Berntsson, R.P.,Fulyani, F.,Majsnerowska, M.,Ter Beek, J.,Poolman, B.,Slotboom, D.J.
The structural basis of modularity in ECF-type ABC transporters.
Nat.Struct.Mol.Biol., 18:755-760, 2011

PubMed Abstract: Energy coupling factor (ECF) transporters are used for the uptake of vitamins in Prokarya. They consist of an integral membrane protein that confers substrate specificity (the S-component) and an energizing module that is related to ATP-binding cassette (ABC) transporters. S-components for different substrates often do not share detectable sequence similarity but interact with the same energizing module. Here we present the crystal structure of the thiamine-specific S-component ThiT from Lactococcus lactis at 2.0 Å. Extensive protein-substrate interactions explain its high binding affinity for thiamine (K(d) ~10(-10) M). ThiT has a fold similar to that of the riboflavin-specific S-component RibU, with which it shares only 14% sequence identity. Two alanines in a conserved motif (AxxxA) located on the membrane-embedded surface of the S-components mediate the interaction with the energizing module. Based on these findings, we propose a general transport mechanism for ECF transporters.

PubMed: 21706007
DOI: 10.1038/nsmb.2073

Experimental method

X-RAY DIFFRACTION (2 Å)