Structure and calcium-binding activity of LipL32, the major surface antigen of pathogenic Leptospira sp.
J Mol Biol
; 390(4): 722-36, 2009 Jul 24.
Article
en En
| MEDLINE
| ID: mdl-19477185
ABSTRACT
Leptospirosis, a spirochaetal zoonotic disease caused by Leptospira, has been recognized as an important emerging infectious disease. LipL32 is the major exposed outer membrane protein found exclusively in pathogenic leptospires, where it accounts for up to 75% of the total outer membrane proteins. It is highly immunogenic, and recent studies have implicated LipL32 as an extracellular matrix binding protein, interacting with collagens, fibronectin, and laminin. In order to better understand the biological role and the structural requirements for the function of this important lipoprotein, we have determined the 2.25-A-resolution structure of recombinant LipL32 protein corresponding to residues 21-272 of the wild-type protein (LipL32(21-272)). The LipL32(21-272) monomer is made of a jelly-roll fold core from which several peripheral secondary structures protrude. LipL32(21-272) is structurally similar to several other jelly-roll proteins, some of which bind calcium ions and extracellular matrix proteins. Indeed, spectroscopic data (circular dichroism, intrinsic tryptophan fluorescence, and extrinsic 1-amino-2-naphthol-4-sulfonic acid fluorescence) confirmed the calcium-binding properties of LipL32(21-272). Ca(2+) binding resulted in a significant increase in the thermal stability of the protein, and binding was specific for Ca(2+) as no structural or stability perturbations were observed for Mg(2+), Zn(2+), or Cu(2+). Careful examination of the crystallographic structure suggests the locations of putative regions that could mediate Ca(2+) binding as well as binding to other interacting host proteins, such as collagens, fibronectin, and laminin.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas de la Membrana Bacteriana Externa
/
Proteínas de Unión al Calcio
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Modelos Moleculares
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Leptospira
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Antígenos Bacterianos
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
J Mol Biol
Año:
2009
Tipo del documento:
Article
País de afiliación:
Brasil