PDBsum entry 4tqv

Transport protein

PDB id: 4tqv

Contents

Protein chains

286 a.a.

284 a.a.

(+ 2 more) 363 a.a.

PDB id:

4tqv

Name:

Transport protein

Title:

Crystal structure of a bacterial abc transporter involved in the import of the acidic polysaccharide alginate

Structure:

Algm1. Chain: a, e, i, m. Fragment: unp residues 25-324. Engineered: yes. Algm2. Chain: b, f, j, n. Engineered: yes. Algs. Chain: c, d, g, h, k, l, o, p.

Source:

Sphingomonas sp.. Organism_taxid: 28214. Gene: algm1. Expressed in: escherichia coli. Expression_system_taxid: 562. Gene: algm2. Gene: algs. Expression_system_taxid: 562

Resolution:

4.50Å R-factor: 0.280 R-free: 0.320

Authors:

Y.Maruyama,T.Itoh,A.Kaneko,Y.Nishitani,B.Mikami,W.Hashimoto,K.Murata

Key ref:

Y.Maruyama et al. (2015). Structure of a Bacterial ABC Transporter Involved in the Import of an Acidic Polysaccharide Alginate. Structure, 23, 1643-1654. PubMed id: 26235029 DOI: 10.1016/j.str.2015.06.021

Date:

12-Jun-14 Release date: 22-Jul-15

Protein chains

Q9KWT8  (Q9KWT8_SPHSX) -  AlgM1 from Sphingomonas sp

Seq: 324 a.a.

Struc: 286 a.a.

Protein chains

Q9KWT7  (Q9KWT7_SPHSX) -  AlgM2 from Sphingomonas sp

Seq: 293 a.a.

Struc: 284 a.a.

Protein chains

Q9KWT9  (Q9KWT9_SPHSX) -  AlgS from Sphingomonas sp

Seq: 363 a.a.

Struc: 363 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

DOI no: 10.1016/j.str.2015.06.021

Structure 23:1643-1654 (2015)

PubMed id: 26235029

Structure of a Bacterial ABC Transporter Involved in the Import of an Acidic Polysaccharide Alginate.

Y.Maruyama, T.Itoh, A.Kaneko, Y.Nishitani, B.Mikami, W.Hashimoto, K.Murata.

ABSTRACT

The acidic polysaccharide alginate represents a promising marine biomass for the microbial production of biofuels, although the molecular and structural characteristics of alginate transporters remain to be clarified. In Sphingomonas sp. A1, the ATP-binding cassette transporter AlgM1M2SS is responsible for the import of alginate across the cytoplasmic membrane. Here, we present the substrate-transport characteristics and quaternary structure of AlgM1M2SS. The addition of poly- or oligoalginate enhanced the ATPase activity of reconstituted AlgM1M2SS coupled with one of the periplasmic solute-binding proteins, AlgQ1 or AlgQ2. External fluorescence-labeled oligoalginates were specifically imported into AlgM1M2SS-containing proteoliposomes in the presence of AlgQ2, ATP, and Mg(2+). The crystal structure of AlgQ2-bound AlgM1M2SS adopts an inward-facing conformation. The interaction between AlgQ2 and AlgM1M2SS induces the formation of an alginate-binding tunnel-like structure accessible to the solvent. The translocation route inside the transmembrane domains contains charged residues suitable for the import of acidic saccharides.