title: Crystal structure of the C-terminal domain of a flagellar hook-capping protein from Xanthomonas campestris.
abstract: The crystal structure of the C-terminal domain of a hook-capping protein FlgD from the plant pathogen Xanthomonas campestris (Xc) has been determined to a resolution of ca 2.5 A using X-ray crystallography. The monomer of whole FlgD comprises 221 amino acids with a molecular mass of 22.7 kDa, but the flexible N-terminus is cleaved for up to 75 residues during crystallization. The final structure of the C-terminal domain reveals a novel hybrid comprising a tudor-like domain interdigitated with a fibronectin type III domain. The C-terminal domain of XcFlgD forms three types of dimers in the crystal. In agreement with this, analytical ultracentrifugation and gel filtration experiments reveal that they form a stable dimer in solution. From these results, we propose that the Xc flagellar hook cap protein FlgD comprises two individual domains, a flexible N-terminal domain that cannot be detected in the current study and a stable C-terminal domain that forms a stable dimer.
authors.affiliation: Institute of Biochemistry, National Chung-Hsing University, Taichung, 40227, Taiwan, Republic of China.
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Kuo
authors.forename: Ko-Hsin
authors.initials: KH
authors.lastname: Chin
authors.forename: Wen-Ting
authors.initials: WT
authors.lastname: Lo
authors.forename: Andrew H-J
authors.initials: AH
authors.lastname: Wang
authors.forename: Shan-Ho
authors.initials: SH
authors.lastname: Chou
mesh_terms: D020816:Amino Acid Motifs; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D005353:Fibronectins / Q000737:chemistry / Q000378:metabolism; D005407:Flagella / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D016959:Xanthomonas campestris / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D005353:Fibronectins