Structural characterization of core-bradavidin in complex with biotin

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Agrawal N, Määttä JAE, Kulomaa MS, Hytönen VP, Johnson MS, Airenne TT
Publisher: Public Library of Science
Publication year: 2017
Journal: PLoS ONE
Volume number: 12
Issue number: 4


Abstract

Bradavidin is a tetrameric biotin-binding protein similar to chicken
avidin and bacterial streptavidin, and was originally cloned from the
nitrogen-fixing bacteria Bradyrhizobium diazoefficiens. We have
previously reported the crystal structure of the full-length, wild-type
(wt) bradavidin with 138 amino acids, where the C-terminal residues
Gly129-Lys138 ("Brad-tag") act as an intrinsic ligand (i.e.
Gly129-Lys138 bind into the biotin-binding site of an adjacent subunit
within the same tetramer) and has potential as an affinity tag for
biotechnological purposes. Here, the X-ray structure of core-bradavidin
lacking the C-terminal residues Gly114-Lys138, and hence missing the
Brad-tag, was crystallized in complex with biotin at 1.60 Å resolution
[PDB:4BBO]. We also report a homology model of rhodavidin, an
avidin-like protein from Rhodopseudomonas palustris, and of an
avidin-like protein from Bradyrhizobium sp. Ai1a-2, both of which have
the Brad-tag sequence at their C-terminus. Moreover, core-bradavidin V1,
an engineered variant of the original core-bradavidin, was also
expressed at high levels in E. coli, as well as a double mutant
(Cys39Ala and Cys69Ala) of core-bradavidin (CC mutant). Our data help us
to further engineer the core-bradavidin-Brad-tag pair for
biotechnological assays and chemical biology applications, and provide
deeper insight into the biotin-binding mode of bradavidin.


Last updated on 2019-16-10 at 03:09