National Center for
5C9L: Crystal structure of native PLL lectin from Photorhabdus luminescens at 1.65 A resolution
A Novel Fucose-binding Lectin from Photorhabdus luminescens (PLL) with an Unusual Heptabladed beta-Propeller Tetrameric Structure
J. Biol. Chem. (2016) 291 p.25032-25049
Photorhabdus luminescens is known for its symbiosis with the entomopathogenic nematode Heterorhabditis bacteriophora and its pathogenicity toward insect larvae. A hypothetical protein from P. luminescens was identified, purified from the native source, and characterized as an l-fucose-binding lectin, named P. luminescens lectin (PLL). Glycan array and biochemical characterization data revealed PLL to be specific toward l-fucose and the disaccharide glycan 3,6-O-Me2-Glcbeta1-4(2,3-O-Me2)Rhaalpha-O-(p-C6H4)-OCH2CH2NH2 PLL was discovered to be a homotetramer with an intersubunit disulfide bridge. The crystal structures of native and recombinant PLL revealed a seven-bladed beta-propeller fold creating seven putative fucose-binding sites per monomer. The crystal structure of the recombinant PLL.l-fucose complex confirmed that at least three sites were fucose-binding. Moreover, the crystal structures indicated that some of the other sites are masked either by the tetrameric nature of the lectin or by incorporation of the C terminus of the lectin into one of these sites. PLL exhibited an ability to bind to insect hemocytes and the cuticular surface of a nematode, H. bacteriophora.