title: Sequence and structural analyses of NSP4 proteins from human group A rotavirus strains detected in Tunisia.
abstract: BACKGROUND
  The NSP4 protein of group A rotavirus (RVA) has been recognized as a viral enterotoxin and plays important roles in viral pathogenesis and morphogenesis. Domains involved in structural and functional interactions have been proposed mainly based on the simian SA11 strain.
  
  
  METHODS
  NSP4 has been classified into 15 different genotypes (E1-E15), and the aim of this study was to analyze the sequences of 46 RVA strains in order to determine the aminoacid (aa) differences between E1 and E2 genotypes. Another aspect was to characterize the structural and physicochemical properties of these strains.
  
  
  RESULTS
  Comparison of deduced aa sequences of the NSP4 protein showed that divergences between NSP4 genotypes E1 and E2 were mostly observed in the VP4-binding, the interspecies variable domain (ISVD) and the double-layered particle (DLP) binding domains. Interestingly, uncommon variations in residues 131 and 138, which are known to be important aa in pathogenesis, were found in one unusual animal derived strain belonging to the E2 genotype. Concerning the structural aspect, no significant differences were noted.
  
  
  CONCLUSIONS
  The presence of punctual aa variations in the NSP4 genotypes may indicate that NSP4 mutates mainly via accumulation of point mutations.
authors.affiliation: UR06SP20, Laboratory of Microbiology, Sahloul University Hospital, 4054 Sousse, Tunisia; Faculty of Pharmacy, University of Monastir, avenue Avicenne, 5019 Monastir, Tunisia.
authors.forename: M
authors.initials: M
authors.lastname: Ben Hadj Fredj
authors.affiliation: UR06SP20, Laboratory of Microbiology, Sahloul University Hospital, 4054 Sousse, Tunisia; Faculty of Pharmacy, University of Monastir, avenue Avicenne, 5019 Monastir, Tunisia.
authors.forename: M
authors.initials: M
authors.lastname: Ben Hamida-Rebaï
authors.affiliation: Laboratory of Clinical and Epidemiological Virology, Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, 1, place de l'Université, 1348 Louvain-La-Neuve, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Zeller
authors.affiliation: Laboratory of Clinical and Epidemiological Virology, Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, 1, place de l'Université, 1348 Louvain-La-Neuve, Belgium.
authors.forename: E
authors.initials: E
authors.lastname: Heylen
authors.affiliation: Laboratory of Clinical and Epidemiological Virology, Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, 1, place de l'Université, 1348 Louvain-La-Neuve, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Van Ranst
authors.affiliation: Laboratory of Clinical and Epidemiological Virology, Department of Microbiology and Immunology, Rega Institute for Medical Research, University of Leuven, 1, place de l'Université, 1348 Louvain-La-Neuve, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Matthijnssens
authors.affiliation: UR06SP20, Laboratory of Microbiology, Sahloul University Hospital, 4054 Sousse, Tunisia; Faculty of Pharmacy, University of Monastir, avenue Avicenne, 5019 Monastir, Tunisia. Electronic address: abdelhalim.trabelsi@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Trabelsi
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001483:Base Sequence; D017124:Conserved Sequence; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics*; D006031:Glycosylation; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D017354:Point Mutation; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012367:RNA, Viral / Q000235:genetics*; D012401:Rotavirus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D012400:Rotavirus Infections / Q000382:microbiology; D016415:Sequence Alignment; D017385:Sequence Homology; D013329:Structure-Activity Relationship; D014118:Toxins, Biological / Q000737:chemistry / Q000235:genetics*; D014416:Tunisia; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics*
chemical_list: D006023:Glycoproteins; C081369:NS28 protein, rotavirus; D012367:RNA, Viral; D014118:Toxins, Biological; D017361:Viral Nonstructural Proteins
keywords: Aminoacid variations; Domain; Domaine; Genotype; Génotype; Mutations; NSP4; Rotavirus