3PPP

Structures of the substrate-binding protein provide insights into the multiple compatible solutes binding specificities of Bacillus subtilis ABC transporter OpuC

Summary for 3PPP

• Entry DOI: 10.2210/pdb3ppp/pdb
• Related: 3PPN 3PPO 3PPQ 3PPR
• Descriptor: Glycine betaine/carnitine/choline-binding protein, TRIMETHYL GLYCINE (3 entities in total)
• Functional Keywords: alpha-beta-alpha sandwich, osmoprotectant, transport protein
• Biological source: Bacillus subtilis
• Cellular location: Cell membrane; Lipid-anchor: O32243
• Total number of polymer chains: 2
• Total formula weight: 70269.85

Authors

Du, Y.,Shi, W.W.,He, Y.X.,Yang, Y.H.,Zhou, C.Z.,Chen, Y. (deposition date: 2010-11-25, release date: 2011-05-11, Last modification date: 2023-11-15)

Primary citation

Du, Y.,Shi, W.W.,He, Y.X.,Yang, Y.H.,Zhou, C.Z.,Chen, Y.
Structures of the substrate-binding protein provide insights into the multiple compatible solute binding specificities of the Bacillus subtilis ABC transporter OpuC
Biochem.J., 436:283-289, 2011

PubMed Abstract: The compatible solute ABC (ATP-binding cassette) transporters are indispensable for acquiring a variety of compatible solutes under osmotic stress in Bacillus subtilis. The substrate-binding protein OpuCC (Opu is osmoprotectant uptake) of the ABC transporter OpuC can recognize a broad spectrum of compatible solutes, compared with its 70% sequence-identical paralogue OpuBC that can solely bind choline. To explore the structural basis of this difference of substrate specificity, we determined crystal structures of OpuCC in the apo-form and in complex with carnitine, glycine betaine, choline and ectoine respectively. OpuCC is composed of two α/β/α globular sandwich domains linked by two hinge regions, with a substrate-binding pocket located at the interdomain cleft. Upon substrate binding, the two domains shift towards each other to trap the substrate. Comparative structural analysis revealed a plastic pocket that fits various compatible solutes, which attributes themultiple-substrate binding property to OpuCC. This plasticity is a gain-of-function via a single-residue mutation of Thr⁹⁴ in OpuCC compared with Asp⁹⁶ in OpuBC.

PubMed: 21366542
DOI: 10.1042/BJ20102097

Experimental method

X-RAY DIFFRACTION (2.4 Å)