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

• Published in: PLoS neglected tropical diseases 2021-11, Vol.15 (11), p.e0009983-e0009983
• Main Authors: Techawiwattanaboon, Teerasit, Thaibankluay, Praparat, Kreangkaiwal, Chahya, Sathean-Anan-Kun, Suwitra, Khaenam, Prasong, Makjaroen, Jiradej, Pisitkun, Trairak, Patarakul, Kanitha
• Format: Article
• Language: English
• Subjects: Abundance; Bacterial Outer Membrane Proteins - chemistry; Bacterial Outer Membrane Proteins - genetics; Bacterial Outer Membrane Proteins - metabolism; Biology and Life Sciences; Biotinylation; Cell surface; Chromatography; Chromatography, High Pressure Liquid; Disease control; Endopeptidase K; Epitopes; Exposure; Gram-negative bacteria; Health aspects; Humans; Identification; Identification and classification; Leptospira interrogans; Leptospira interrogans serovar pomona - chemistry; Leptospira interrogans serovar pomona - genetics; Leptospira interrogans serovar pomona - metabolism; Leptospirosis; Leptospirosis - microbiology; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Medicine and Health Sciences; Membrane proteins; Molecules; Outer membrane proteins; Pathogens; Peptides; Proteinase; Proteins; Proteolysis; Proteomics; Research and Analysis Methods; Scientific imaging; Shaving; Software; Tandem Mass Spectrometry; Tropical diseases; Vaccines; Virulence
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0009983

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.