title: A recombinant horseshoe crab plasma lectin recognizes specific pathogen-associated molecular patterns of bacteria through rhamnose.
abstract: Horseshoe crab is an ancient marine arthropod that, in the absence of a vertebrate-like immune system, relies solely on innate immune responses by defense molecules found in hemolymph plasma and granular hemocytes for host defense. A plasma lectin isolated from the hemolymph of Taiwanese Tachypleus tridentatus recognizes bacteria and lipopolysaccharides (LPSs), yet its structure and mechanism of action remain unclear, largely because of limited availability of horseshoe crabs and the lack of a heterogeneous expression system. In this study, we have successfully expressed and purified a soluble and functional recombinant horseshoe crab plasma lectin (rHPL) in an Escherichia coli system. Interestingly, rHPL bound not only to bacteria and LPSs like the native HPL but also to selective medically important pathogens isolated from clinical specimens, such as Gram-negative Pseudomonas aeruginosa and Klebsiella pneumoniae and Gram-positive Streptococcus pneumoniae serotypes. The binding was demonstrated to occur through a specific molecular interaction with rhamnose in pathogen-associated molecular patterns (PAMPs) on the bacterial surface. Additionally, rHPL inhibited the growth of P. aeruginosa PAO1 in a concentration-dependent manner. The results suggest that a specific protein-glycan interaction between rHPL and rhamnosyl residue may further facilitate development of novel diagnostic and therapeutic strategies for microbial pathogens.
authors.affiliation: Institute of Molecular and Cellular Biology & Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
authors.forename: Sim-Kun
authors.initials: SK
authors.lastname: Ng
authors.affiliation: Institute of Molecular and Cellular Biology & Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
authors.forename: Yu-Tsyr
authors.initials: YT
authors.lastname: Huang
authors.affiliation: Institute of Molecular and Cellular Biology & Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China; Department of Biology, Johns Hopkins University, Baltimore, Maryland, United States of America.
authors.forename: Yuan-Chuan
authors.initials: YC
authors.lastname: Lee
authors.affiliation: Institute of Molecular and Cellular Biology & Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
authors.forename: Ee-Ling
authors.initials: EL
authors.lastname: Low
authors.affiliation: Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan Hsien, Taiwan, Republic of China.
authors.forename: Cheng-Hsun
authors.initials: CH
authors.lastname: Chiu
authors.affiliation: Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan Hsien, Taiwan, Republic of China.
authors.forename: Shiu-Ling
authors.initials: SL
authors.lastname: Chen
authors.affiliation: Simpson Biotech Co., Ltd., Kuei Shan, Taoyuan County, Taiwan, Republic of China.
authors.forename: Liang-Chi
authors.initials: LC
authors.lastname: Mao
authors.affiliation: Institute of Molecular and Cellular Biology & Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan, Republic of China.
authors.forename: Margaret Dah-Tsyr
authors.initials: MD
authors.lastname: Chang
mesh_terms: D000818:Animals; D060829:Arthropod Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D002942:Circular Dichroism; D006737:Horseshoe Crabs / Q000378:metabolism; D007711:Klebsiella pneumoniae / Q000378:metabolism; D037102:Lectins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012210:Rhamnose / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000187:drug effects; D013296:Streptococcus pneumoniae / Q000378:metabolism
chemical_list: D060829:Arthropod Proteins; D001426:Bacterial Proteins; D037102:Lectins; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; C425303:Tachypleus plasma lectin-1; D012210:Rhamnose