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Structure and Sialyllactose Binding of the Carboxy-Terminal Head Domain of the Fibre from a Siadenovirus, Turkey Adenovirus 3.

Singh AK, Berbís MÁ, Ballmann MZ, Kilcoyne M, Menéndez M, Nguyen TH, Joshi L, Cañada FJ, Jiménez-Barbero J, Benkő M, Harrach B, van Raaij MJ - PLoS ONE (2015)

Bottom Line: The carboxy-terminal region of its fibre does not have significant sequence similarity to any other adenovirus fibre heads of known structure.It binds slightly more strongly to the avirulent form.We propose that, in vivo, the TAdV-3 fibre may bind a sialic acid-containing cell surface component.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Estructura de Macromoléculas, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain.

ABSTRACT
The virulent form of turkey adenovirus 3 (TAdV-3), also known as turkey hemorrhagic enteritis virus (THEV), is an economically important poultry pathogen, while the avirulent form is used as a vaccine. TAdV-3 belongs to the genus Siadenovirus. The carboxy-terminal region of its fibre does not have significant sequence similarity to any other adenovirus fibre heads of known structure. Two amino acid sequence differences between virulent and avirulent TAdV-3 map on the fibre head: where virulent TAdV-3 contains Ile354 and Thr376, avirulent TAdV-3 contains Met354 and Met376. We determined the crystal structures of the trimeric virulent and avirulent TAdV-3 fibre head domains at 2.2 Å resolution. Each monomer contains a beta-sandwich, which, surprisingly, resembles reovirus fibre head more than other adenovirus fibres, although the ABCJ-GHID topology is conserved in all. A beta-hairpin insertion in the C-strand of each trimer subunit embraces its neighbouring monomer. The avirulent and virulent TAdV-3 fibre heads are identical apart from the exact orientation of the beta-hairpin insertion. In vitro, sialyllactose was identified as a ligand by glycan microarray analysis, nuclear magnetic resonance spectroscopy, and crystallography. Its dissociation constant was measured to be in the mM range by isothermal titration calorimetry. The ligand binds to the side of the fibre head, involving amino acids Glu392, Thr419, Val420, Lys421, Asn422, and Gly423 binding to the sialic acid group. It binds slightly more strongly to the avirulent form. We propose that, in vivo, the TAdV-3 fibre may bind a sialic acid-containing cell surface component.

No MeSH data available.


Related in: MedlinePlus

TAdV-3 fibre head binding to a glycan microarray.A histogram representing the fluorescence intensity of TAdV-3 bound to presented glycans on the microarray surface detected by fluorescently-labelled anti-His antibody is shown. Histograms represent the average of three replicate experiments and error bars depict one standard deviation of the mean calculated over three microarray slides. The broken line represents the binding threshold (approximately five times background).
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pone.0139339.g006: TAdV-3 fibre head binding to a glycan microarray.A histogram representing the fluorescence intensity of TAdV-3 bound to presented glycans on the microarray surface detected by fluorescently-labelled anti-His antibody is shown. Histograms represent the average of three replicate experiments and error bars depict one standard deviation of the mean calculated over three microarray slides. The broken line represents the binding threshold (approximately five times background).

Mentions: Glycan microarray profiling of the His-tagged TAdV-3 fibre head protein was performed with a library of 71 glycoconjugates (Fig 6; S1 Table). The protein showed substantial interaction with two sialylated glycans, 3'- and 6'-sialyllactose. The observed fluorescence intensities were 5,000 and 6,100 RFU for 3'- and 6'-sialyllactose, respectively, which was significantly higher than the experimental binding threshold of approximately 1,600 RFU (five times background; Fig 6) [60, 63]. No binding inhibition was observed in the presence of lactose or galactose, indicating that the sialic acid portions of the carbohydrates were mainly involved in contact with the proteins. Xylose linked to bovine serum albumin through a 4-aminophenyl linker was also identified as a potential ligand, although the biological significance of this result is doubtful, as terminal xylose units are only found in plant glycans. Interestingly, TAdV-3 did not bind to 3'-sialyl-N-acetyllactosamine (3SLNBSA), as is found in N-linked oligosaccharides on glycoproteins, or to glycoproteins including bovine fetuin and transferrin, which have both 3'- and 6'-sialyl-N-acetyllactosamine terminal structures (Fig 6).


Structure and Sialyllactose Binding of the Carboxy-Terminal Head Domain of the Fibre from a Siadenovirus, Turkey Adenovirus 3.

Singh AK, Berbís MÁ, Ballmann MZ, Kilcoyne M, Menéndez M, Nguyen TH, Joshi L, Cañada FJ, Jiménez-Barbero J, Benkő M, Harrach B, van Raaij MJ - PLoS ONE (2015)

TAdV-3 fibre head binding to a glycan microarray.A histogram representing the fluorescence intensity of TAdV-3 bound to presented glycans on the microarray surface detected by fluorescently-labelled anti-His antibody is shown. Histograms represent the average of three replicate experiments and error bars depict one standard deviation of the mean calculated over three microarray slides. The broken line represents the binding threshold (approximately five times background).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4587935&req=5

pone.0139339.g006: TAdV-3 fibre head binding to a glycan microarray.A histogram representing the fluorescence intensity of TAdV-3 bound to presented glycans on the microarray surface detected by fluorescently-labelled anti-His antibody is shown. Histograms represent the average of three replicate experiments and error bars depict one standard deviation of the mean calculated over three microarray slides. The broken line represents the binding threshold (approximately five times background).
Mentions: Glycan microarray profiling of the His-tagged TAdV-3 fibre head protein was performed with a library of 71 glycoconjugates (Fig 6; S1 Table). The protein showed substantial interaction with two sialylated glycans, 3'- and 6'-sialyllactose. The observed fluorescence intensities were 5,000 and 6,100 RFU for 3'- and 6'-sialyllactose, respectively, which was significantly higher than the experimental binding threshold of approximately 1,600 RFU (five times background; Fig 6) [60, 63]. No binding inhibition was observed in the presence of lactose or galactose, indicating that the sialic acid portions of the carbohydrates were mainly involved in contact with the proteins. Xylose linked to bovine serum albumin through a 4-aminophenyl linker was also identified as a potential ligand, although the biological significance of this result is doubtful, as terminal xylose units are only found in plant glycans. Interestingly, TAdV-3 did not bind to 3'-sialyl-N-acetyllactosamine (3SLNBSA), as is found in N-linked oligosaccharides on glycoproteins, or to glycoproteins including bovine fetuin and transferrin, which have both 3'- and 6'-sialyl-N-acetyllactosamine terminal structures (Fig 6).

Bottom Line: The carboxy-terminal region of its fibre does not have significant sequence similarity to any other adenovirus fibre heads of known structure.It binds slightly more strongly to the avirulent form.We propose that, in vivo, the TAdV-3 fibre may bind a sialic acid-containing cell surface component.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Estructura de Macromoléculas, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain.

ABSTRACT
The virulent form of turkey adenovirus 3 (TAdV-3), also known as turkey hemorrhagic enteritis virus (THEV), is an economically important poultry pathogen, while the avirulent form is used as a vaccine. TAdV-3 belongs to the genus Siadenovirus. The carboxy-terminal region of its fibre does not have significant sequence similarity to any other adenovirus fibre heads of known structure. Two amino acid sequence differences between virulent and avirulent TAdV-3 map on the fibre head: where virulent TAdV-3 contains Ile354 and Thr376, avirulent TAdV-3 contains Met354 and Met376. We determined the crystal structures of the trimeric virulent and avirulent TAdV-3 fibre head domains at 2.2 Å resolution. Each monomer contains a beta-sandwich, which, surprisingly, resembles reovirus fibre head more than other adenovirus fibres, although the ABCJ-GHID topology is conserved in all. A beta-hairpin insertion in the C-strand of each trimer subunit embraces its neighbouring monomer. The avirulent and virulent TAdV-3 fibre heads are identical apart from the exact orientation of the beta-hairpin insertion. In vitro, sialyllactose was identified as a ligand by glycan microarray analysis, nuclear magnetic resonance spectroscopy, and crystallography. Its dissociation constant was measured to be in the mM range by isothermal titration calorimetry. The ligand binds to the side of the fibre head, involving amino acids Glu392, Thr419, Val420, Lys421, Asn422, and Gly423 binding to the sialic acid group. It binds slightly more strongly to the avirulent form. We propose that, in vivo, the TAdV-3 fibre may bind a sialic acid-containing cell surface component.

No MeSH data available.


Related in: MedlinePlus