Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Acinetobacter baumannii [ICD11:
XN8LS 
]
The structure was elucidated in this paperNCBI PubMed ID: 28209973Publication DOI: 10.1038/srep42711Journal NLM ID: 101563288Publisher: London: Nature Publishing Group
Correspondence: huangkf
gate.sinica.edu.tw; shwu
gate.sinica.edu.tw
Institutions: Master program in Microbiology and Immunology, Tzu Chi University, Hualien 970, Taiwan, Genomics Research Center, Academia Sinica, Taipei 115, Taiwan, Core Facilities for Protein Structural Analysis (CFPSA), Academia Sinica, Taipei 115, Taiwan, Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan, Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan
With an increase in antibiotic-resistant strains, the nosocomial pathogen Acinetobacter baumannii has become a serious threat to global health. Glycoconjugate vaccines containing fragments of bacterial exopolysaccharide (EPS) are an emerging therapeutic to combat bacterial infection. Herein, we characterize the bacteriophage PhiAB6 tailspike protein (TSP), which specifically hydrolyzed the EPS of A. baumannii strain 54149 (Ab-54149). Ab-54149 EPS exhibited the same chemical structure as two antibiotic-resistant A. baumannii strains. The PhiAB6 TSP-digested products comprised oligosaccharides of two repeat units, typically with stoichiometric pseudaminic acid (Pse). The 1.48-1.89-A resolution crystal structures of an N-terminally-truncated PhiAB6 TSP and its complexes with the semi-hydrolyzed products revealed a trimeric beta-helix architecture that bears intersubunit carbohydrate-binding grooves, with some features unusual to the TSP family. The structures suggest that Pse in the substrate is an important recognition site for PhiAB6 TSP. A region in the carbohydrate-binding groove is identified as the determinant of product specificity. The structures also elucidated a retaining mechanism, for which the catalytic residues were verified by site-directed mutagenesis. Our findings provide a structural basis for engineering the enzyme to produce desired oligosaccharides, which is useful for the development of glycoconjugate vaccines against A. baumannii infection.
Acinetobacter baumannii, pseudaminic acid, crystal structure, bacteriophage, glycoconjugate vaccine, Tailspike
Structure type: polymer chemical repeating unit
Location inside paper: p.3
Compound class: EPS
Contained glycoepitopes: IEDB_130648,IEDB_134627,IEDB_136044,IEDB_137472,IEDB_137473,IEDB_141794,IEDB_142488,IEDB_146664,IEDB_147450,IEDB_190606,IEDB_983931,SB_165,SB_166,SB_187,SB_192,SB_195,SB_21,SB_23,SB_24,SB_7,SB_8,SB_88
Methods: 13C NMR, 1H NMR, gel filtration, NMR-2D, X-ray, SDS-PAGE, DNA techniques, crystallization, LC-ESI-MS, LC-ESI-MS/MS, enzyme kinetic assay, bacteriophage digestion, substrate binding
Biosynthesis and genetic data: genetic data
Comments, role: major repeat units
3D data: 3D structure of ΦAB6 TSP
Related record ID(s): 11929, 12158, 12159
NCBI Taxonomy refs (TaxIDs): 470Reference(s) to other database(s): GTC:G74492VS
Show glycosyltransferases
There is only one chemically distinct structure:
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