4CII
Crystal structure of N-terminally truncated Helicobacter pylori T4SS Protein CagL as domain swapped dimer
Summary for 4CII
| Entry DOI | 10.2210/pdb4cii/pdb |
| Descriptor | CAG PATHOGENICITY ISLAND PROTEIN (CAG18), (4R)-2-METHYLPENTANE-2,4-DIOL (3 entities in total) |
| Functional Keywords | protein binding, adhesion, rgd motif, integrin binding, type iv secretion, t4s, virulence, hp0539 |
| Biological source | HELICOBACTER PYLORI |
| Total number of polymer chains | 1 |
| Total formula weight | 25865.41 |
| Authors | Barden, S.,Schomburg, B.,Niemann, H.H. (deposition date: 2013-12-09, release date: 2014-02-19, Last modification date: 2024-10-16) |
| Primary citation | Barden, S.,Schomburg, B.,Conradi, J.,Backert, S.,Sewald, N.,Niemann, H.H. Structure of a Three-Dimensional Domain-Swapped Dimer of the Helicobacter Pylori Type Iv Secretion System Pilus Protein Cagl. Acta Crystallogr.,Sect.D, 70:1391-, 2014 Cited by PubMed Abstract: A new crystal form of the Helicobacter pylori type IV secretion system (T4SS) pilus protein CagL is described here. In contrast to two previously reported monomeric structures, CagL forms a three-dimensional domain-swapped dimer. CagL dimers can arise during refolding from inclusion bodies or can form spontaneously from purified monomeric CagL in the crystallization conditions. Monomeric CagL forms a three-helix bundle, with which the N-terminal helix is only loosely associated. In the new crystal form, the N-terminal helix is missing. The domain swap is owing to exchange of the C-terminal helix between the two protomers of a dimer. A loop-to-helix transition results in a long helix of 108 amino acids comprising the penultimate and the last helix of the monomer. The RGD motif of dimeric CagL adopts an α-helical conformation. In contrast to the previously reported structures, the conserved and functionally important C-terminal hexapeptide is resolved. It extends beyond the three-helix bundle as an exposed helical appendage. This new crystal form contributes to the molecular understanding of CagL by highlighting rigid and flexible regions in the protein and by providing the first view of the C-terminus. Based on the structural features, a previously unrecognized homology between CagL and CagI is discussed. PubMed: 24816107DOI: 10.1107/S1399004714003150 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.15 Å) |
Structure validation
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