0000000000206521
AUTHOR
Oded Livnah
showing 6 related works from this author
Factors Dictating the Pseudocatalytic Efficiency of Avidins
2006
The hydrolysis of biotinyl p-nitrophenyl ester (BNP) by a series of avidin derivatives was examined. Surprisingly, a hyperthermostable avidin-related protein (AVR4) was shown to display extraordinary yet puzzling hydrolytic activity. In order to evaluate the molecular determinants that contribute to the reaction, the crystal structure of AVR4 was compared with those of avidin, streptavidin and key mutants of the two proteins in complex with biotinyl p-nitroanilide (BNA), the inert amide analogue of BNP. The structures revealed that a critical lysine residue contributes to the hydrolysis of BNP by avidin but has only a minor contribution to the AVR4-mediated reaction. Indeed, the respective …
Design and construction of highly stable, protease-resistant chimeric avidins.
2005
The chicken avidin gene family consists of avidin and seven separate avidin-related genes (AVRs) 1-7. Avidin protein is a widely used biochemical tool, whereas the other family members have only recently been produced as recombinant proteins and characterized. In our previous study, AVR4 was found to be the most stable biotin binding protein thus far characterized (T(m) = 106.4 degrees C). In this study, we studied further the biotin-binding properties of AVR4. A decrease in the energy barrier between the biotin-bound and unbound state of AVR4 was observed when compared with that of avidin. The high resolution structure of AVR4 facilitated comparison of the structural details of avidin and …
Dimer-tetramer transition between solution and crystalline states of streptavidin and avidin mutants.
2003
ABSTRACT The biotin-binding tetrameric proteins, streptavidin from Streptomyces avidinii and chicken egg white avidin, are excellent models for the study of subunit-subunit interactions of a multimeric protein. Efforts are thus being made to prepare mutated forms of streptavidin and avidin, which would form monomers or dimers, in order to examine their effect on quaternary structure and assembly. In the present communication, we compared the crystal structures of binding site W→K mutations in streptavidin and avidin. In solution, both mutant proteins are known to form dimers, but upon crystallization, both formed tetramers with the same parameters as the native proteins. All of the intersub…
Crystallization and preliminary X-ray analysis of W120K mutant of streptavidin.
2001
Bacterial streptavidin and chicken avidin are homotetrameric proteins that share an exceptionally high affinity towards the vitamin biotin. The biotin-binding sites in both proteins contain a crucial tryptophan residue contributed from an adjacent subunit. This particular tryptophan (W110 in avidin and W120 in streptavidin) plays an important role in both biotin binding and in the quaternary stabilities of the proteins. An intriguing naturally occurring alteration of tryptophan to lysine was previously described in the C-terminal domain of sea-urchin fibropellins, which share a relatively high sequence similarity with avidin and streptavidin. Avidin (Avm-W110K) and streptavidin (Savm-W120K)…
High-resolution crystal structure of an avidin-related protein: insight into high-affinity biotin binding and protein stability.
2004
The chicken avidin gene belongs to an extended gene family encoding seven avidin-related genes (AVRs), of which only avidin is expressed in the chicken. The sequences of AVR4 and AVR5 are identical and the common protein (AVR4) has been expressed both in insect and bacterial systems. The recombinant proteins are similarly hyperthermostable and bind biotin with similarly high affinities. AVR4 was crystallized in the apo and biotin-complexed forms and their structures were determined at high resolution. Its tertiary and quaternary structures are very similar to those of avidin and streptavidin. Its biotin-binding site shows only a few alterations compared with those of avidin and streptavidin…
Biotin Induces Tetramerization of a Recombinant Monomeric Avidin
2001
Chicken avidin, a homotetramer that binds four molecules of biotin was converted to a monomeric form by successive mutations of interface residues to alanine. The major contribution to monomer formation was the mutation of two aspartic acid residues, which together account for ten hydrogen bonding interactions at the 1-4 interface. Mutation of these residues, together with the three hydrophobic residues at the 1-3 interface, led to stable monomer formation in the absence of biotin. Upon addition of biotin, the monomeric avidin reassociated to the tetramer, which exhibited properties similar to those of native avidin, with respect to biotin binding, thermostability, and protease resistance. …