PDBsum entry 4q4h

Hydrolase/transport protein

PDB id: 4q4h

Contents

Protein chains

572 a.a.

583 a.a.

Waters ×12

PDB id:

4q4h

Name:

Hydrolase/transport protein

Title:

Tm287/288 in its apo state

Structure:

Abc transporter. Chain: a. Synonym: abc transporter, atp-binding protein, lipid a export atp- binding/permease protein msba. Engineered: yes. Uncharacterized abc transporter atp-binding protein tm_0288. Chain: b. Engineered: yes

Source:

Thermotoga maritima. Organism_taxid: 243274. Strain: atcc 43589 / msb8 / dsm 3109 / jcm 10099. Gene: tm_0287, thema_03290, tmari_0285. Expressed in: escherichia coli. Expression_system_taxid: 562. Gene: tm_0288. Expression_system_taxid: 562

Resolution:

2.53Å R-factor: 0.240 R-free: 0.290

Authors:

M.Hohl,M.G.Gruetter,M.A.Seeger

Key ref:

M.Hohl et al. (2014). Structural basis for allosteric cross-talk between the asymmetric nucleotide binding sites of a heterodimeric ABC exporter. Proc Natl Acad Sci U S A, 111, 11025-11030. PubMed id: 25030449 DOI: 10.1073/pnas.1400485111

Date:

14-Apr-14 Release date: 16-Jul-14

Protein chain

Q9WYC3  (Q9WYC3_THEMA) -  ABC transporter, ATP-binding protein from Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8)

Seq: 577 a.a.

Struc: 572 a.a.*

Protein chain

Q9WYC4  (Y288_THEMA) -  Uncharacterized ABC transporter ATP-binding protein TM_0288 from Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8)

Seq: 598 a.a.

Struc: 583 a.a.

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

Enzyme reactions

• Enzyme class: Chains A, B: E.C.?

DOI no: 10.1073/pnas.1400485111

Proc Natl Acad Sci U S A 111:11025-11030 (2014)

PubMed id: 25030449

Structural basis for allosteric cross-talk between the asymmetric nucleotide binding sites of a heterodimeric ABC exporter.

M.Hohl, L.M.Hürlimann, S.Böhm, J.Schöppe, M.G.Grütter, E.Bordignon, M.A.Seeger.

ABSTRACT

ATP binding cassette (ABC) transporters mediate vital transport processes in every living cell. ATP hydrolysis, which fuels transport, displays positive cooperativity in numerous ABC transporters. In particular, heterodimeric ABC exporters exhibit pronounced allosteric coupling between a catalytically impaired degenerate site, where nucleotides bind tightly, and a consensus site, at which ATP is hydrolyzed in every transport cycle. Whereas the functional phenomenon of cooperativity is well described, its structural basis remains poorly understood. Here, we present the apo structure of the heterodimeric ABC exporter TM287/288 and compare it to the previously solved structure with adenosine 5'-(β,γ-imido)triphosphate (AMP-PNP) bound at the degenerate site. In contrast to other ABC exporter structures, the nucleotide binding domains (NBDs) of TM287/288 remain in molecular contact even in the absence of nucleotides, and the arrangement of the transmembrane domains (TMDs) is not influenced by AMP-PNP binding, a notion confirmed by double electron-electron resonance (DEER) measurements. Nucleotide binding at the degenerate site results in structural rearrangements, which are transmitted to the consensus site via two D-loops located at the NBD interface. These loops owe their name from a highly conserved aspartate and are directly connected to the catalytically important Walker B motif. The D-loop at the degenerate site ties the NBDs together even in the absence of nucleotides and substitution of its aspartate by alanine is well-tolerated. By contrast, the D-loop of the consensus site is flexible and the aspartate to alanine mutation and conformational restriction by cross-linking strongly reduces ATP hydrolysis and substrate transport.