Identification of the Sialic Acid Structures Recognized by Minute Virus of Mice and the Role of Binding Affinity in Virulence Adaptation*
- Hyun-Joo Nam‡,
- Brittney Gurda-Whitaker‡,
- Wand Yee Gan‡,
- Shawen Ilaria‡,
- Robert McKenna‡,
- Padmaja Mehta§,
- Richard A. Alvarez¶ and
- Mavis Agbandje-McKenna‡1
- ‡Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610, and the §Cardiovascular Biology Research Program, The Oklahoma Medical Research Foundation and ¶Department of Biochemistry and Molecular Biology, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73104
- 1 To whom correspondence should be addressed. Tel.: 352-392-5694; Fax: 352-392-3422; E-mail:mckenna{at}ufl.edu.
Abstract
Sialic acid binding is required for infectious cell surface receptor recognition by parvovirus minute virus of mice (MVM). We have utilized a glycan array consisting of ∼180 different carbohydrate structures to identify the specific sialosides recognized by the prototype (MVMp) and immunosuppressive (MVMi) strains of MVM plus three virulent mutants of MVMp, MVMp-I362S, MVMp-K368R, and MVMp-I362S/K368R. All of the MVM capsids specifically bound to three structures with a terminal sialic acid-linked α2-3 to a common Galβ1-4GlcNAc motif: Neu5Acα2-3Galβ1-4GlcNAcβ1-4Galβ1-4GlcNAc (3′SiaLN-LN), Neu5Acα2-3Galβ1-4GlcNAcβ1-3Galβ1-4GlcNAcβ1-3Galβ1-4GlcNAc (3′SiaLN-LN-LN), and Neu5Acα2-3Galβ1-4(Fucα1-3)-GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAcβ1-3Galβ1-4(Fucα1-3)GlcNAc (sLex-Lex-Lex). In addition, MVMi also recognized four multisialylated glycans with terminal α2-8 linkages: Neu5Acα2-8Neu5Acα2-8Neu5Acα ((Sia)3), Neu5Acα2-8Neu5Acα2-3Galβ1-4Glc (GD3), Neu5Acα2-8Neu5Acα2-8Neu5Acα2-3Galβ1-4Glc (GT3), and Neu5Acα2-8Neu5Acα2-3(GalNAcβ1-4)Galβ1-4Glc (GD2). Interestingly, the virulent MVMp-K368R mutant also recognized GT3. Analysis of the relative binding affinities using a surface plasmon resonance biospecific interaction (BIAcore) assay showed the wild-type MVMp and MVMi capsids binding with higher affinity to selected glycans compared with the virulent MVMp mutants. The reduced affinity of the virulent MVMp mutants are consistent with previous in vitro cell binding assays that had shown weaker binding to permissive cells compared with wild-type MVMp. This study identifies the sialic acid structures recognized by MVM. It also provides rationale for the tropism of MVM for malignant transformed cells that contain sLex motifs and the neurotropism of MVMi, which is likely mediated via interactions with multisialylated glycans known to be tumor cell markers. Finally, the observations further implicate a decreased binding affinity for sialic acid in the in vivo adaptation of MVMp to a virulent phenotype.
Footnotes
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↵2 The abbreviations used are: MVM, minute virus of mice; MVMp, prototype strain of MVM; MVMi, immunosuppressive strain of MVM; SCID, severe combined immunodeficient; VP, viral protein; wt, wild-type; VLP, virus-like particle; SPR, surface plasmon resonance; S/N, signal-to-noise.
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↵3 The compound library was produced by the Consortium for Functional Glycomics, functionalglycomics.org.
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↵* This study was supported by National Science Foundation Grant MCB 0212846 (to M. A.-M.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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- Received May 9, 2006.
- Revision received July 5, 2006.
- The American Society for Biochemistry and Molecular Biology, Inc.
