1b44
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CRYSTAL STRUCTURE OF THE B SUBUNIT OF HEAT-LABILE ENTEROTOXIN FROM E. COLI CARRYING A PEPTIDE WITH ANTI-HSV ACTIVITY
OverviewOverview
Two chimeric proteins, consisting of the B subunit of Escherichia coli, heat-labile enterotoxin with different peptides fused to the COOH-terminal, ends, have been crystallized and their three-dimensional structure, determined. The two extensions correspond to (a) a nonapeptide, representing the COOH-terminal sequence of the small subunit of herpes, simplex virus type 1 ribonucleotide reductase and (b) a 27-amino acid long, peptide, corresponding to the COOH-terminal end of the catalytic subunit, (POL) of DNA polymerase from the same virus. Both proteins crystallize in, the P41212 space group with one pentameric molecule per asymmetric unit, corresponding to a solvent content of about 75%. The overall conformation, of the B subunit pentamer in the two chimeric proteins, which consists of, five identical polypeptide chains, is very similar to that in the native, AB complex and conforms strictly to 5-fold symmetry. On the contrary, the, peptide extensions are essentially disordered: in the case of the, nonapeptide, only 5 and 6 amino acids were, respectively, positioned in, two monomers, while in the other three only 2 residues are ordered. The, extension is fully confined to the surface of the pentamer opposite to the, face that interacts with the membrane and consequently it does not, interfere with the ability of the B subunit to interact with membrane, receptors. Moreover, the conformational flexibility of the two peptide, extensions could be correlated to their propensity for proteolytic, processing and consequent release of a biologically active molecule into, cultured cells.
About this StructureAbout this Structure
1B44 is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the B subunit of Escherichia coli heat-labile enterotoxin carrying peptides with anti-herpes simplex virus type 1 activity., Matkovic-Calogovic D, Loregian A, D'Acunto MR, Battistutta R, Tossi A, Palu G, Zanotti G, J Biol Chem. 1999 Mar 26;274(13):8764-9. PMID:10085117
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