title: Crystal structure of a secreted lipase from Gibberella zeae reveals a novel "double-lock" mechanism.
abstract: Fusarium graminearum (sexual stage: Gibberella zeae) is the causative agent of Fusarium Head Blight (FHB), which is one of the most destructive plant disease of cereals, accounting for high grain yield losses, especially for wheat and maize. Like other fungal pathogens, several extracellular enzymes secreted by G. zeae are known to be involved in host infection. Among these secreted lipases, G. zeae lipase (GZEL), which is encoded by the FGL1 gene, was demonstrated to be crucial to G. zeae pathogenicity. However, the precise mechanism of GZEL remains unclear due to a lack of detailed structural information. In this study, we report the crystal structure of GZEL at the atomic level. The structure of GZEL displays distinct structural differences compared to reported homologues and indicates a unique "double lock" enzymatic mechanism. To gain insight into substrate/inhibitor recognition, we proposed a model of GZEL in complex with substrate and the lipase inhibitor ebelactone B (based on the reported structures of GZEL homologues), which defines possible substrate binding sites within the catalytic cleft and suggests an "anti sn-l" binding mode. These results pave the way to elucidating the mechanism of GZEL and thus provide clues for the design of anti-FHB inhibitors.
authors.affiliation: Laboratory of Structural Biology, Tsinghua University, Beijing 100084, China.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Lou
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Yuna
authors.initials: Y
authors.lastname: Sun
authors.forename: Ye
authors.initials: Y
authors.lastname: Liu
authors.forename: Zheng
authors.initials: Z
authors.lastname: Liu
authors.forename: Wenping
authors.initials: W
authors.lastname: Wu
authors.forename: Zihe
authors.initials: Z
authors.lastname: Rao
mesh_terms: D000595:Amino Acid Sequence; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D005874:Gibberella / Q000201:enzymology*; D007783:Lactones / Q000737:chemistry; D008049:Lipase / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019301:Oleic Acid / Q000737:chemistry; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013499:Surface Properties
chemical_list: D007783:Lactones; D019301:Oleic Acid; C030795:ebelactone B; D008049:Lipase