title: Identification of staphylococcal lipoteichoic acid-binding proteins in human serum by high-resolution LTQ-Orbitrap mass spectrometry.
abstract: Lipoteichoic acid (LTA), a major virulence factor of Gram-positive bacteria, is associated with bacterial adherence to host cells, biofilm formation, and inflammation. LTA-binding proteins (LTA-BPs) play an important role in the host immune response by initially recognizing and responding to LTA during infections. In this study, we screened for LTA-BPs in human serum using LTA-immobilized beads and high-throughput mass spectrometry. Highly pure and structurally intact LTA was prepared from Staphylococcus aureus and immobilized onto N-hydroxysuccinimide-activated Sepharose(®) 4 Fast Flow beads. The immobilization process does not seem to affect the biological activity of LTA since LTA-immobilized beads could stimulate macrophages and activate Toll-like receptor 2. Then, the LTA-immobilized beads were incubated with the human serum to capture LTA-BPs and their molecular identities were determined using high-resolution LTQ-Orbitrap hybrid Fourier transform mass spectrometry. LTA-BPs captured at high frequencies were neutrophil-activating peptide 2, prohibitin-2, alpha-1-anti-trypsin, histidine-rich glycoprotein, apolipoproteins, complements, and coagulation factor, most of which are known to be related with the host immune responses against infections. As high-throughput, efficient, accurate and sensitive, this screening method could be widely applicable to the identification of novel binding proteins to microbial virulence factors with glycolipid structures.
authors.affiliation: Institute of Molecular Biology and Genetics, Interdisciplinary Program for Biochemical Engineering and Biotechnology, Seoul National University, Seoul 151-742, Republic of Korea.
authors.forename: Kyoung-Soon
authors.initials: KS
authors.lastname: Jang
authors.forename: Jung Eun
authors.initials: JE
authors.lastname: Baik
authors.forename: Seok-Seong
authors.initials: SS
authors.lastname: Kang
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Jeon
authors.forename: Seulggie
authors.initials: S
authors.lastname: Choi
authors.forename: Yung-Hun
authors.initials: YH
authors.lastname: Yang
authors.forename: Byung-Gee
authors.initials: BG
authors.lastname: Kim
authors.forename: Cheol-Heui
authors.initials: CH
authors.lastname: Yun
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Han
mesh_terms: D002352:Carrier Proteins / Q000097:blood*; D006801:Humans; D008070:Lipopolysaccharides / Q000097:blood* / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D013210:Staphylococcus / Q000737:chemistry / Q000302:isolation & purification*; D013682:Teichoic Acids / Q000097:blood* / Q000737:chemistry
chemical_list: D002352:Carrier Proteins; D008070:Lipopolysaccharides; D013682:Teichoic Acids; C009900:lipoteichoic acid