Summary of the biochemical properties and phylogeny of avidin (AVD) and the AVRs. The putative chicken biotin-binding proteins BBP-A and BBP-B  as well as streptavidin (STR) are included. The confidence levels of the branching of the phylogenetic tree were assessed using the bootstrap method . The tree is unrooted and the branch lengths are not to scale. The values at each node represent the percentage of the 1000 trees where the species above the node are consistently found. Tm(-), heat-induced unfolding temperature without D-biotin (°C). Tm(+), heat-induced unfolding temperature in the presence of D-biotin (°C). Tr(-), transition temperature of oligomeric disassembly without D-biotin determined using SDS-PAGE assay (°C) . Tr(+), transition temperature of oligomeric disassembly in the presence of D-biotin (°C). kdiss, biotin dissociation rate constant (× 10-6 s-1) obtained from global fitting  of the 3H-biotin dissociation data. I1–3, three residues important for the 1–3 subunit interface (equivalent to residues 94, 113 and 115 in AVR2). The residues in BBP-A and BBP-B are numbered according to avidin. N. D., not determined. aHytönen VP, unpublished data. Analysis performed on wt proteins produced in the baculovirus expression system as described in Ref. . bFrom Ref. . cFrom Ref. . dFrom Ref. . eFrom Ref. .