1iud
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MALTODEXTRIN-BINDING PROTEIN INSERTION/DELETION MUTANT WITH AN INSERTED B-CELL EPITOPE FROM THE PRES2 REGION OF HEPATITIS B VIRUS
OverviewOverview
We report the crystal structure of MalE-B133, a recombinant form of the, maltodextrin-binding protein (MBP) of Escherichia coli carrying an, inserted amino-acid sequence of a B-cell epitope from the preS2 region of, the hepatitis B virus (HBV). The structure was determined by molecular, replacement methods and refined to 2.7 A resolution. MalE-B133 is an, insertion/deletion mutant of MBP in which residues from positions 134 to, 142, an external alpha helix in the wild-type structure, are replaced by a, foreign peptide segment of 19 amino acids. The inserted residues, correspond to the preS2 sequence from positions 132 to 145 and five, flanking residues that arise from the creation of restriction sites. The, conformation of the recombinant protein, excluding the inserted segment, closely resembles that of wild-type MBP in the closed maltose-bound form., MalE-B133 was shown by previous studies to display certain immunogenic and, antigenic properties of the hepatitis B surface antigen (HBsAg), which, contains the preS2 region. The crystal structure reveals the conformation, of the first nine epitope residues (preS2 positions 132 to 140) exposed on, the surface of the molecule. The remaining five epitope residues (preS2, positions 141 to 145) are not visible in electron density maps. The path, of the polypeptide chain in the visible portion of the insert differs from, that of the deleted segment in the structure of wild-type MBP, displaying, a helical conformation at positions 134 to 140 (preS2 sequence numbering)., A tripeptide (Asp-Pro-Arg) at the N terminus of the helix forms a stable, structural motif that may be implicated in the cross-reactivity of, anti-HBsAg antibodies with the hybrid protein.
About this StructureAbout this Structure
1IUD is a Single protein structure of sequence from Escherichia coli with MAL as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of a recombinant form of the maltodextrin-binding protein carrying an inserted sequence of a B-cell epitope from the preS2 region of hepatitis B virus., Saul FA, Vulliez-le Normand B, Lema F, Bentley GA, Proteins. 1997 Jan;27(1):1-8. PMID:9037707
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