title: Conserved asparagine residue 54 of alpha-sarcin plays a role in protein stability and enzyme activity.
abstract: Asparagine 54 of alpha-sarcin is a conserved residue within the proteins of the ribotoxin family of microbial ribonucleases. It is located in loop 2 of the protein, which lacks repetitive secondary structure elements but exhibits a well-defined conformation. Five mutant variants at this residue have been produced and characterized. The spectroscopic characterization of these proteins indicates that the overall conformation is not changed upon mutation. Activity and denaturation assays show that Asn-54 largely contributes to protein stability, and its presence is a requirement for the highly specific inhibitory activity of these ribotoxins on ribosomes.
authors.affiliation: Departamento de Bioquímica y Biología Molecular I, Facultad de Química, Universidad Complutense, E-28040 Madrid, Spain.
authors.forename: Ansgar
authors.initials: A
authors.lastname: Siemer
authors.forename: Manuel
authors.initials: M
authors.lastname: Masip
authors.forename: Nelson
authors.initials: N
authors.lastname: Carreras
authors.forename: Lucía
authors.initials: L
authors.lastname: García-Ortega
authors.forename: Mercedes
authors.initials: M
authors.lastname: Oñaderra
authors.forename: Marta
authors.initials: M
authors.lastname: Bruix
authors.forename: Alvaro Martínez
authors.initials: AM
authors.lastname: Del Pozo
authors.forename: José G
authors.initials: JG
authors.lastname: Gavilanes
mesh_terms: D019943:Amino Acid Substitution; D001216:Asparagine / Q000737:chemistry*; D017124:Conserved Sequence; D004247:DNA / Q000737:chemistry; D004722:Endoribonucleases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D011487:Protein Conformation; D011489:Protein Denaturation; D011506:Proteins / Q000737:chemistry*; D012265:Ribonucleotides / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013379:Substrate Specificity; D013816:Thermodynamics
chemical_list: D005656:Fungal Proteins; D011506:Proteins; D012265:Ribonucleotides; C014801:alpha-sarcin; D001216:Asparagine; D004247:DNA; D004722:Endoribonucleases