1wbi

From Proteopedia

Revision as of 15:26, 5 November 2007

AVR2

Overview

BACKGROUND: The chicken avidin gene family consists of avidin and several, avidin related genes (AVRs). Of these gene products, avidin is the best, characterized and is known for its extremely high affinity for D-biotin, a, property that is utilized in numerous modern life science applications., Recently, the AVR genes have been expressed as recombinant proteins, which, have shown different biotin-binding properties as compared to avidin., RESULTS: In the present study, we have employed multiple biochemical, methods to better understand the structure-function relationship of AVR, proteins focusing on AVR2. Firstly, we have solved the high-resolution, crystal structure of AVR2 in complex with a bound ligand, D-biotin. The, AVR2 structure reveals an overall fold similar to the previously, determined structures of avidin and AVR4. Major differences are seen, especially at the 1-3 subunit interface, which is stabilized mainly by, polar interactions in the case of AVR2 but by hydrophobic interactions in, the case of AVR4 and avidin, and in the vicinity of the biotin binding, pocket. Secondly, mutagenesis, competitive dissociation analysis and, differential scanning calorimetry were used to compare and study the, biotin-binding properties as well as the thermal stability of AVRs and, avidin. These analyses pinpointed the importance of residue 109 for biotin, binding and stability of AVRs. The I109K mutation increased the, biotin-binding affinity of AVR2, whereas the K109I mutation decreased the, biotin-binding affinity of AVR4. Furthermore, the thermal stability of, AVR2(I109K) increased in comparison to the wild-type protein and the K109I, mutation led to a decrease in the thermal stability of AVR4. CONCLUSION:, Altogether, this study broadens our understanding of the structural, features determining the ligand-binding affinities and stability as well, as the molecular evolution within the protein family. This novel, information can be applied to further develop and improve the tools, already widely used in avidin-biotin technology.

About this Structure

1WBI is a Single protein structure of sequence from Gallus gallus with SO4, BTN and GOL as ligands. Structure known Active Site: AC1. Full crystallographic information is available from OCA.

Reference

Avidin related protein 2 shows unique structural and functional features among the avidin protein family., Hytonen VP, Maatta JA, Kidron H, Halling KK, Horha J, Kulomaa T, Nyholm TK, Johnson MS, Salminen TA, Kulomaa MS, Airenne TT, BMC Biotechnol. 2005 Oct 7;5:28. PMID:16212654

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