title: Identification of Oligosaccharides in Human Milk Bound onto the Toxin A Carbohydrate Binding Site of Clostridium difficile.
abstract: The oligosaccharides in human milk constitute a major innate immunological mechanism by which breastfed infants gain protection against infectious diarrhea. Clostridium difficile is the most important cause of nosocomial diarrhea, and the C-terminus of toxin A with its carbohydrate binding site, TcdA-f2, demonstrates specific abolishment of cytotoxicity and receptor binding activity upon diethylpyrocarbonate modification of the histidine residues in TcdA. TcdA-f2 was cloned and expressed in E. coli BL21 (DE3). A human milk oligosaccharide (HMO) mixture displayed binding with TcdA-f2 at 38.2 respond units (RU) at the concentration of 20 μg/ml, whereas the eight purified HMOs showed binding with the carbohydrate binding site of TcdA-f2 at 3.3 to 14 RU depending on their structures via a surface plasma resonance biosensor. Among them, Lacto-N-fucopentaose V (LNFPV) and Lacto-N-neohexaose (LNnH) demonstrated tight binding to TcdA-f2 with docking energy of -9.48 kcal/mol and -12.81 kcal/mol, respectively. It displayed numerous hydrogen bonding and hydrophobic interactions with amino acid residues of TcdA-f2.
authors.affiliation: Institute of Food Industrialization, Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang 25354, Republic of Korea.
authors.forename: Thi Thanh Hanh
authors.initials: TT
authors.lastname: Nguyen
authors.affiliation: Department of Obstetrics and Gynecology, Chonnam National University Medical School, Gwangju 61469, Republic of Korea.
authors.forename: Jong Woon
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Amorepacific Corp. R&D Ctr., Gyeonggi-do 17074, Republic of Korea.
authors.forename: Jun-Seong
authors.initials: JS
authors.lastname: Park
authors.affiliation: Amorepacific Corp. R&D Ctr., Gyeonggi-do 17074, Republic of Korea.
authors.forename: Kyeong Hwan
authors.initials: KH
authors.lastname: Hwang
authors.affiliation: Institute of Food Industrialization, Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang 25354, Republic of Korea.
authors.forename: Tae-Su
authors.initials: TS
authors.lastname: Jang
authors.affiliation: Institute of Food Industrialization, Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang 25354, Republic of Korea.
authors.forename: Chun-Hyung
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Institute of Food Industrialization, Institutes of Green Bio Science & Technology, Seoul National University, Pyeongchang 25354, Republic of Korea.|Graduate School of International Agricultural Technology, Seoul National University, Pyeongchang 25354, Republic of Korea.
authors.forename: Doman
authors.initials: D
authors.lastname: Kim
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry; D001427:Bacterial Toxins / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D016360:Clostridioides difficile / Q000737:chemistry* / Q000378:metabolism; D004768:Enterotoxins / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D007223:Infant; D008895:Milk, Human / Q000737:chemistry*; D062105:Molecular Docking Simulation; D009844:Oligosaccharides / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D020349:Surface Plasmon Resonance
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004768:Enterotoxins; D009844:Oligosaccharides; C041348:tcdA protein, Clostridium difficile
keywords: Clostridium difficile; human milk oligosaccharides; molecular docking; surface plasmon resonance; toxin A