PDBsum entry 1a7l

Transport

PDB id: 1a7l

Contents

Protein chains

380 a.a. *

Ligands

GLC-GLC ×3

Waters ×48

* Residue conservation analysis

PDB id:

1a7l

Name:

Transport

Title:

Dominant b-cell epitope from the pres2 region of hepatitis b virus in the form of an inserted peptide segment in maltodextrin-binding protein

Structure:

Male-b363. Chain: a, b, c. Engineered: yes

Source:

Synthetic construct. Organism_taxid: 32630. Strain: ed9. Gene: mbp mutant. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.90Å R-factor: 0.192 R-free: 0.286

Authors:

F.A.Saul,B.Vulliez-Lenormand,F.Lema,G.A.Bentley

Key ref:

F.A.Saul et al. (1998). Crystal structure of a dominant B-cell epitope from the preS2 region of hepatitis B virus in the form of an inserted peptide segment in maltodextrin-binding protein. J Mol Biol, 280, 185-192. PubMed id: 9654443 DOI: 10.1006/jmbi.1998.1866

Date:

16-Mar-98 Release date: 17-Jun-98

Protein chains

P0AEX9  (MALE_ECOLI) -  Maltose/maltodextrin-binding periplasmic protein from Escherichia coli (strain K12)

Seq: 396 a.a.

Struc: 380 a.a.*

* PDB and UniProt seqs differ at 7 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1006/jmbi.1998.1866

J Mol Biol 280:185-192 (1998)

PubMed id: 9654443

Crystal structure of a dominant B-cell epitope from the preS2 region of hepatitis B virus in the form of an inserted peptide segment in maltodextrin-binding protein.

F.A.Saul, B.Vulliez-le Normand, F.Lema, G.A.Bentley.

ABSTRACT

We report here the crystal structure of MalE-B363, a recombinant construction of maltodextrin-binding protein bearing a dominant B-cell epitope sequence from the preS2 region of the hepatitis B surface antigen. The inserted peptide sequence, which replaces the seven carboxy-terminal residues of maltodextrin-binding protein, carries the 14 amino acid residue epitope contained between residues 132 and 145 from the preS2 region. The epitope sequence is flanked on either side by additional residues that result from the genetically engineered insertion, bringing the total length of the foreign peptide to 26 amino acid residues. The hybrid protein has been previously shown to be recognised by monoclonal antibodies elicited by the native viral antigen. Three independent molecules of MalE-B363 are present in the asymmetric unit of the crystal. All 14 epitope residues could be traced for one molecule, ten epitope residues had significant electron density for the second, but no density was visible for the epitope of the third. The conformation of the amino-terminal segment of the epitope from Gln132(e) to Gly138(e) is similar in the two molecules of MalE-B363 for which the foreign peptide could be traced. Moreover, the conformation of a smaller segment, comprising residues Asp133(e) to Arg137(e), is similar to that present in the previously determined crystal structure of MalE-B133, another insertion/deletion mutant of maltodextrin-binding protein bearing the preS2 epitope. The presence of a common structural motif for the same sequence in disparate molecular environments suggests that this conformation might be present also in the native viral antigen. This could provide a structural basis to explain the cross-reactivity of anti-preS2 monoclonal antibodies with these hybrid proteins.

Selected figure(s)

Figure 1.
Figure 1. Schematic view of MalE-B363 in stereo; (a) molecule 1 and (b) molecule 2. The genetically inserted peptide at the carboxy terminus of the hybrid is shown in red and the bound molecule of maltose is shown in blue. Illustrations were produced by MOLSCRIPT [Kraulis 1991].

Figure 2.
Figure 2. Stereo view of the electron density corresponding to the genetically inserted peptide in MalE-B363 (a) from residues 364(i) to 383(i) in molecule 1 and (b) from residues 364(i) to 141(e) in molecule 2. Contours are drawn at the 1 r.m.s. level of a (2F[o]−F[c]) electron density map. No significant electron density was observed for the epitope insertion in molecule 3.

The above figures are reprinted by permission from Elsevier: J Mol Biol (1998, 280, 185-192) copyright 1998.

Figures were selected by an automated process.