ABSTRACT
Rotavirus nonstructural protein 4, the first viral enterotoxin to be identified, is a multidomain, multifunctional glycoprotein. Earlier, we reported a Ca2+-bound coiled-coil tetrameric structure of the diarrhea-inducing region of NSP4 from the rotavirus strains SA11 and I321 and a Ca2+-free pentameric structure from the rotavirus strain ST3, all with a parallel arrangement of α-helices. pH was found to determine the oligomeric state: a basic pH favoured a tetramer, whereas an acidic pH favoured a pentamer. Here, we report two novel forms of the coiled-coil region of NSP4 from the bovine rotavirus strains MF66 and NCDV. These crystallized at acidic pH, forming antiparallel coiled-coil tetrameric structures without any bound Ca2+ ion. Structural and mutational studies of the coiled-coil regions of NSP4 revealed that the nature of the residue at position 131 (Tyr/His) plays an important role in the observed structural diversity.
Subject(s)
Calcium/chemistry , Glycoproteins/chemistry , Rotavirus/chemistry , Toxins, Biological/chemistry , Viral Nonstructural Proteins/chemistry , Amino Acid Motifs , Binding Sites , Calcium/metabolism , Cations, Divalent , Cloning, Molecular , Crystallography, X-Ray , Escherichia coli/genetics , Escherichia coli/metabolism , Gene Expression , Genetic Vectors/chemistry , Genetic Vectors/metabolism , Glycoproteins/genetics , Glycoproteins/metabolism , Hydrogen Bonding , Hydrogen-Ion Concentration , Models, Molecular , Protein Binding , Protein Conformation, alpha-Helical , Protein Interaction Domains and Motifs , Protein Multimerization , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Rotavirus/genetics , Thermodynamics , Toxins, Biological/genetics , Toxins, Biological/metabolism , Viral Nonstructural Proteins/genetics , Viral Nonstructural Proteins/metabolismABSTRACT
Orf, or contagious ecthyma, a highly contagious transboundary disease of sheep and goats, is caused by a double-stranded DNA virus (ORFV) belonging to the genus Parapoxvirus of the family Poxviridae. The ORFV genome encodes the major envelope proteins B2L and F1L, which have been found to be highly immunogenic and have multiple functional characteristics. In order to investigate the functional properties of the B2L protein, in this study, the B2L gene of ORFV strain 59/05, encoding recombinant mature B2L (aa 1M-D334), was produced as a fusion protein in Escherichia coli. The functional characteristics of purified rB2L fusion protein (~60 kDa) were evaluated in vivo and in vitro, showing that this protein had lipase and immunomodulatory activities. Immunization trials involving laboratory animals (mice, rabbits and guinea pigs) using either constant or graded doses of rB2L fusion protein with or without adjuvants (FCA, alum) as well as co-administration with candidate rErns-Ag protein of classical swine fever virus (CSFV) indicated that the rB2L protein is immunogenic and has immunomodulatory properties. This study shows the potential utility of the rB2L protein as a safe and novel adjuvant in veterinary vaccine formulations.
Subject(s)
Ecthyma, Contagious/virology , Orf virus/immunology , Viral Envelope Proteins/immunology , Viral Vaccines/immunology , Animals , Ecthyma, Contagious/immunology , Escherichia coli/genetics , Escherichia coli/metabolism , Female , Guinea Pigs , Immunization , Lipase/administration & dosage , Lipase/genetics , Lipase/immunology , Male , Mice , Orf virus/genetics , Rabbits , Recombinant Proteins/administration & dosage , Recombinant Proteins/genetics , Recombinant Proteins/immunology , Recombination, Genetic , Viral Envelope Proteins/administration & dosage , Viral Envelope Proteins/genetics , Viral Vaccines/administration & dosage , Viral Vaccines/geneticsABSTRACT
Orbital pseudotumor is a benign disease involving the orbital structures. Pseudotumor of the ciliary body is rare. We present a case of a 27-year-old male who presented with gradual visual loss, pain, and redness in his left eye. On examination he was found to have a yellowish white mass at the periphery of anterior chamber in his left eye and ultrasound biomicroscopy (UBM) revealed a ciliary body mass in the same eye. He was treated with systemic steroids, which was tapered over a period of 8 weeks. His symptoms improved and the ciliary body mass disappeared with no recurrence over the next 6 months. UBM is an important diagnostic tool for diagnosing ciliary body mass. Early diagnosis and prompt treatment with systemic steroids may help resolve pseudotumor of the ciliary body.
