title: Crystal structure of LipL32, the most abundant surface protein of pathogenic Leptospira spp.
abstract: Spirochetes of the genus Leptospira cause leptospirosis in humans and animals worldwide. Proteins exposed on the bacterial cell surface are implicated in the pathogenesis of leptospirosis. However, the biological role of the majority of these proteins is unknown; this is principally due to the lack of genetic systems for investigating Leptospira and the absence of any structural information on leptospiral antigens. To address this, we have determined the 2.0-A-resolution structure of the lipoprotein LipL32, the most abundant outer-membrane and surface protein present exclusively in pathogenic Leptospira species. The extracellular domain of LipL32 revealed a compact, globular, "jelly-roll" fold from which projected an unusual extended beta-hairpin that served as a principal mediator of the observed crystallographic dimer. Two acid-rich patches were also identified as potential binding sites for positively charged ligands, such as laminin, to which LipL32 has a propensity to bind. Although LipL32 shared no significant sequence identity to any known protein, it possessed structural homology to the adhesins that bind components of the extracellular matrix, suggesting that LipL32 functions in an analogous manner. Moreover, the structure provides a framework for understanding the immunological role of this major surface lipoprotein.
authors.affiliation: The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Julian P
authors.initials: JP
authors.lastname: Vivian
authors.forename: Travis
authors.initials: T
authors.lastname: Beddoe
authors.forename: Adrian D
authors.initials: AD
authors.lastname: McAlister
authors.forename: Matthew C J
authors.initials: MC
authors.lastname: Wilce
authors.forename: Leyla
authors.initials: L
authors.lastname: Zaker-Tabrizi
authors.forename: Sally
authors.initials: S
authors.lastname: Troy
authors.forename: Emma
authors.initials: E
authors.lastname: Byres
authors.forename: David E
authors.initials: DE
authors.lastname: Hoke
authors.forename: Paul A
authors.initials: PA
authors.lastname: Cullen
authors.forename: Miranda
authors.initials: M
authors.lastname: Lo
authors.forename: Gerald L
authors.initials: GL
authors.lastname: Murray
authors.forename: Ben
authors.initials: B
authors.lastname: Adler
authors.forename: Jamie
authors.initials: J
authors.lastname: Rossjohn
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000737:chemistry / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D001483:Base Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D019281:Dimerization; D006801:Humans; D007919:Leptospira / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000472:pathogenicity; D008074:Lipoproteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D008958:Models, Molecular; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D055672:Static Electricity
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; C406589:LipL32 protein, Leptospira; D008074:Lipoproteins; D011994:Recombinant Proteins