Surface proteomics and label-free quantification of Leptospira interrogans serovar Pomona.

Teerasit Techawiwattanaboon,Praparat Thaibankluay,Suwitra Sathean-Anan-Kun,Trairak Pisitkun,Jiradej Makjaroen,Kanitha Patarakul,Prasong Khaenam,Chahya Kreangkaiwal,Tao Lin

doi:10.1371/journal.pntd.0009983

Teerasit Techawiwattanaboon, Praparat Thaibankluay + Show 7 more

Open Access

https://doi.org/10.1371/journal.pntd.0009983

Copy DOI

Abstract

Leptospirosis is a re-emerging zoonosis with a global distribution. Surface-exposed outer membrane proteins (SE-OMPs) are crucial for bacterial–host interactions. SE-OMPs locate and expose their epitope on cell surface where is easily accessed by host molecules. This study aimed to screen for surface-exposed proteins and their abundance profile of pathogenic Leptospira interrogans serovar Pomona. Two complementary approaches, surface biotinylation and surface proteolytic shaving, followed by liquid chromatography tandem-mass spectrometry (LC-MS/MS) were employed to identify SE-OMPs of intact leptospires. For quantitative comparison, in-depth label-free analysis of SE-OMPs obtained from each method was performed using MaxQuant. The total number of proteins identified was 1,001 and 238 for surface biotinylation and proteinase K shaving, respectively. Among these, 39 were previously known SE-OMPs and 68 were predicted to be localized on the leptospiral surface. Based on MaxQuant analysis for relative quantification, six known SE-OMPs including EF- Tu, LipL21, LipL41, LipL46, Loa22, and OmpL36, and one predicted SE-OMPs, LipL71 were found in the 20 most abundant proteins, in which LipL41 was the highest abundant SE-OMP. Moreover, uncharacterized LIC14011 protein (LIP3228 ortholog in serovar Pomona) was identified as a novel predicted surface βb-OMP. High-abundance leptospiral SE-OMPs identified in this study may play roles in virulence and infection and are potential targets for development of vaccine or diagnostic tests for leptospirosis.

Highlights

Leptospirosis is a neglected zoonosis with high global prevalence, mainly in tropical and subtropical regions including Southeast Asia, Oceania, the Indian subcontinent, Caribbean, and Latin America [1,2]
This study aimed to identify SE-outer membrane proteins (OMPs) of pathogenic L. interrogans serovar Pomona using surface biotinylation and proteinase K shaving methods comprehensively
Most leptospires were stained with SYTO9, which indicated intact cells, before (Fig 2A) and after (Fig 2B) biotin labeling suggesting that the membrane integrity was mainly preserved after the labeling process

Summary

Introduction

Leptospirosis is a neglected zoonosis with high global prevalence, mainly in tropical and subtropical regions including Southeast Asia, Oceania, the Indian subcontinent, Caribbean, and Latin America [1,2]. Leptospirosis causes approximately 1.03 million cases and 58,900 deaths annually worldwide [3]. The major etiologic agent of the illness is pathogenic Leptospira spp., but some cases are associated with intermediate species such as L. inadai and L. wolffii [4]. Most wild and domestic animals can be reservoir hosts harboring the pathogens in their kidneys. Humans are considered as accidental hosts by direct contact with leptospires shed in urine of infected animals or indirect exposure to water or soil contaminated with the urine [2]

Objectives

Methods

Results

Conclusion