LipL41, a Hemin Binding Protein from Leptospira santarosai serovar Shermani

Ming-Hsing Lin,Yi-Ching Ko,Yuan-Chih Chang,Chwan-Deng Hsiao,Min-Shi Wang,Yuh-Ju Sun,Shih-Hsun Huang,Chih-Wei Yang,Ben Adler

doi:10.1371/journal.pone.0083246

Abstract

Leptospirosis is one of the most widespread zoonotic diseases in the world. It is caused by the pathogen Leptospira that results in multiple-organ failure, in particular of the kidney. Outer membrane lipoprotein is the suspected virulence factor of Leptospira. In Leptospira spp LipL41 is one major lipoprotein and is highly conserved. Previous study suggests that LipL41 bears hemin-binding ability and might play a possible role in iron regulation and storage. However, the characterization of hemin-binding ability of LipL41 is still unclear. Here the hemin-binding ability of LipL41 was examined, yielding a K d = 0.59 ± 0.14 μM. Two possible heme regulatory motifs (HRMs), C[P/S], were found in LipL41 at 140Cys-Ser and 220Cys-Pro. The mutation study indicates that Cys140 and Cys220 might be cooperatively involved in hemin binding. A supramolecular assembly of LipL41 was determined by transmission electron microscopy. The LipL41 oligomer consists of 36 molecules and folds as a double-layered particle. At the C-terminus of LipL41, there are two tetratricopeptide repeats (TPRs), which might be involved in the protein-protein interaction of the supramolecular assembly.

Highlights

Leptospirosis is one of the most widespread zoonotic diseases in the world and is caused by the pathogen Leptospira [1,2]
We found that LipL41 forms a supermolecule to bind hemin and a heminbinding pocket composed of two heme regulatory motifs, 140Cys-Ser and 220Cys-Pro, was identified
The availability of free iron is highly restricted with heme being the most abundant form of organic iron; the ability to utilize heme compounds is important in pathogenic bacteria

Summary

Introduction

Leptospirosis is one of the most widespread zoonotic diseases in the world and is caused by the pathogen Leptospira [1,2]. The major target of Leptospira in the kidney is the renal proximal tubular cells, and the pretreatment with Leptospira outer membrane proteins (OMPs) leads to tubulointerstitial nephritis and acute renal malfunction [2,5,6]. The proteins (OMPs) and lipopolysaccharides on leptospiral outer membrane are the major antigens that result in immunity to Leptospira and might be responsible for renal dysfunction [7,8,9]. Leptospiral OMPs are likely to be involved in the hostpathogen interactions [8,10,11] They elicit inflammation and lead to tubular injuries through Toll-like receptor-dependent pathways. Many leptospiral lipoproteins have been identified as virulence factors involved in etiology and pathogenesis of leptospirosis

Methods

Results

Conclusion