title: Binding properties of HABA-type azo derivatives to avidin and avidin-related protein 4.
abstract: The chicken genome encodes several biotin-binding proteins, including avidin and avidin-related protein 4 (AVR4). In addition to D-biotin, avidin binds an azo dye compound, 4-hydroxyazobenzene-2-carboxylic acid (HABA), but the HABA-binding properties of AVR4 are not yet known. Differential scanning calorimetry, UV/visible spectroscopy, and molecular modeling were used to analyze the binding of 15 azo molecules to avidin and AVR4. Significant differences are seen in azo compound preferences for the two proteins, emphasizing the importance of the loop between strands beta3 and beta4 for azo ligand recognition; information on these loops is provided by the high-resolution (1.5 A) X-ray structure for avidin reported here. These results may be valuable in designing improved tools for avidin-based life science and nanobiotechnology applications.
authors.affiliation: Department of Biochemistry and Pharmacy, Abo Akademi University, Tykistökatu 6, FI-20520 Turku, Finland.
authors.forename: Susanna
authors.initials: S
authors.lastname: Repo
authors.forename: Tiina A
authors.initials: TA
authors.lastname: Paldanius
authors.forename: Vesa P
authors.initials: VP
authors.lastname: Hytönen
authors.forename: Thomas K M
authors.initials: TK
authors.lastname: Nyholm
authors.forename: Katrin K
authors.initials: KK
authors.lastname: Halling
authors.forename: Juhani
authors.initials: J
authors.lastname: Huuskonen
authors.forename: Olli T
authors.initials: OT
authors.lastname: Pentikäinen
authors.forename: Kari
authors.initials: K
authors.lastname: Rissanen
authors.forename: J Peter
authors.initials: JP
authors.lastname: Slotte
authors.forename: Tomi T
authors.initials: TT
authors.lastname: Airenne
authors.forename: Tiina A
authors.initials: TA
authors.lastname: Salminen
authors.forename: Markku S
authors.initials: MS
authors.lastname: Kulomaa
authors.forename: Mark S
authors.initials: MS
authors.lastname: Johnson
mesh_terms: D000818:Animals; D030161:Avian Proteins / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D001360:Avidin / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D001391:Azo Compounds / Q000737:chemistry* / Q000494:pharmacology; D001665:Binding Sites; D002152:Calorimetry, Differential Scanning; D002645:Chickens; D018360:Crystallography, X-Ray; D006023:Glycoproteins / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D010047:Ovalbumin / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D011487:Protein Conformation; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
chemical_list: D030161:Avian Proteins; D001391:Azo Compounds; D006023:Glycoproteins; D008024:Ligands; D001360:Avidin; C001413:HABA; D010047:Ovalbumin