PDBsum entry 4qc2

Transport protein

PDB id: 4qc2

Contents

Protein chains

235 a.a.

Ligands

ATP ×2

Metals

_MG ×2

Waters ×144

PDB id:

4qc2

Name:

Transport protein

Title:

Crystal structure of lipopolysaccharide transport protein lptb in complex with atp and magnesium ions

Structure:

Abc transporter related protein. Chain: a, b. Fragment: nucleotide-binding protein. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 536056. Strain: k12. Gene: lptb, ecdh1_0506, ecdh1me8569_3090. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.22Å R-factor: 0.184 R-free: 0.248

Authors:

Z.Wang,Q.Xiang,X.Zhu,H.Dong,C.He,H.Wang,Y.Zhang,W.Wang,C.Dong

Key ref:

Z.Wang et al. (2014). Structural and functional studies of conserved nucleotide-binding protein LptB in lipopolysaccharide transport. Biochem Biophys Res Commun, 452, 443-449. PubMed id: 25172661 DOI: 10.1016/j.bbrc.2014.08.094

Date:

09-May-14 Release date: 22-Oct-14

Protein chains

C9QY46  (C9QY46_ECOD1) -

DOI no: 10.1016/j.bbrc.2014.08.094

Biochem Biophys Res Commun 452:443-449 (2014)

PubMed id: 25172661

Structural and functional studies of conserved nucleotide-binding protein LptB in lipopolysaccharide transport.

Z.Wang, Q.Xiang, X.Zhu, H.Dong, C.He, H.Wang, Y.Zhang, W.Wang, C.Dong.

ABSTRACT

Lipopolysaccharide (LPS) is the main component of the outer membrane of Gram-negative bacteria, which plays an essential role in protecting the bacteria from harsh conditions and antibiotics. LPS molecules are transported from the inner membrane to the outer membrane by seven LPS transport proteins. LptB is vital in hydrolyzing ATP to provide energy for LPS transport, however this mechanism is not very clear. Here we report wild-type LptB crystal structure in complex with ATP and Mg(2+), which reveals that its structure is conserved with other nucleotide-binding proteins (NBD). Structural, functional and electron microscopic studies demonstrated that the ATP binding residues, including K42 and T43, are crucial for LptB's ATPase activity, LPS transport and the vitality of Escherichia coli cells with the exceptions of H195A and Q85A; the H195A mutation does not lower its ATPase activity but impairs LPS transport, and Q85A does not alter ATPase activity but causes cell death. Our data also suggest that two protomers of LptB have to work together for ATP hydrolysis and LPS transport. These results have significant impacts in understanding the LPS transport mechanism and developing new antibiotics.