title: Bradavidin II from Bradyrhizobium japonicum: a new avidin-like biotin-binding protein.
abstract: A gene encoding an avidin-like protein was discovered in the genome of B. japonicum. The gene was cloned to an expression vector and a protein, named bradavidin II, was produced in E. coli. Bradavidin II has an identity of 20-30% and a similarity of 30-40% with previously discovered bradavidin and other avidin-like proteins. It has biochemical characteristics close to those of avidin and streptavidin and binds biotin tightly. In contrast to other tetrameric avidin-like proteins studied to date, bradavidin II has no tryptophan analogous to the W110 in avidin (W120 in streptavidin), thought to be one of the most essential residues for tight biotin-binding. Homology modeling suggests that a proline residue may function analogously to tryptophan in this particular position. Structural elements of bradavidin II such as an interface residue pattern or biotin contact residues could be used as such or transferred to engineered avidin forms to improve or create new tools for biotechnological applications.
authors.affiliation: Institute of Medical Technology, Biokatu 6, FI-33014 University of Tampere and Tampere University Hospital, Finland.
authors.forename: Satu H
authors.initials: SH
authors.lastname: Helppolainen
authors.forename: Juha A E
authors.initials: JA
authors.lastname: Määttä
authors.forename: Katrin K
authors.initials: KK
authors.lastname: Halling
authors.forename: J Peter
authors.initials: JP
authors.lastname: Slotte
authors.forename: Vesa P
authors.initials: VP
authors.lastname: Hytönen
authors.forename: Janne
authors.initials: J
authors.lastname: Jänis
authors.forename: Pirjo
authors.initials: P
authors.lastname: Vainiotalo
authors.forename: Markku S
authors.initials: MS
authors.lastname: Kulomaa
authors.forename: Henri R
authors.initials: HR
authors.lastname: Nordlund
mesh_terms: D000595:Amino Acid Sequence; D001360:Avidin / Q000378:metabolism*; D001483:Base Sequence; D001710:Biotin / Q000378:metabolism*; D020369:Bradyrhizobium / Q000737:chemistry*; D002151:Calorimetry; D002352:Carrier Proteins / Q000302:isolation & purification* / Q000378:metabolism; D017931:DNA Primers; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D021122:Protein Subunits / Q000302:isolation & purification* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D002352:Carrier Proteins; D017931:DNA Primers; D021122:Protein Subunits; C501304:bradavidin protein, Bradyrhizobium japonicum; D001360:Avidin; D001710:Biotin