PDBsum entry 2uz2

Glycoprotein

PDB id: 2uz2

Contents

Protein chains

115 a.a. *

119 a.a. *

Ligands

ACT

BTN

Waters ×208

* Residue conservation analysis

PDB id:

2uz2

Name:

Glycoprotein

Title:

Crystal structure of xenavidin

Structure:

Xenavidin. Chain: a, d. Engineered: yes

Source:

Xenopus tropicalis. Western clawed frog. Organism_taxid: 8364. Expressed in: spodoptera frugiperda. Expression_system_taxid: 7108. Expression_system_cell_line: sf9.

Resolution:

1.70Å R-factor: 0.183 R-free: 0.216

Authors:

S.H.Helppolainen,J.A.E.Maatta,T.T.Airenne,M.S.Johnson,M.S.Kulomaa, H.R.Nordlund

Key ref:

J.A.Määttä et al. (2009). Structural and functional characteristics of xenavidin, the first frog avidin from Xenopus tropicalis. Bmc Struct Biol, 9, 63-63. PubMed id: 19788720

Date:

24-Apr-07 Release date: 03-Jun-08

Protein chain

A7YYL1  (A7YYL1_XENTR) -  Avd protein from Xenopus tropicalis

Seq: 148 a.a.

Struc: 115 a.a.*

Protein chain

A7YYL1  (A7YYL1_XENTR) -  Avd protein from Xenopus tropicalis

Seq: 148 a.a.

Struc: 119 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Bmc Struct Biol 9:63-63 (2009)

PubMed id: 19788720

Structural and functional characteristics of xenavidin, the first frog avidin from Xenopus tropicalis.

J.A.Määttä, S.H.Helppolainen, V.P.Hytönen, M.S.Johnson, M.S.Kulomaa, T.T.Airenne, H.R.Nordlund.

ABSTRACT

BACKGROUND: Avidins are proteins with extraordinarily high ligand-binding affinity, a property which is used in a wide array of life science applications. Even though useful for biotechnology and nanotechnology, the biological function of avidins is not fully understood. Here we structurally and functionally characterise a novel avidin named xenavidin, which is to our knowledge the first reported avidin from a frog. RESULTS: Xenavidin was identified from an EST sequence database for Xenopus tropicalis and produced in insect cells using a baculovirus expression system. The recombinant xenavidin was found to be homotetrameric based on gel filtration analysis. Biacore sensor analysis, fluorescently labelled biotin and radioactive biotin were used to evaluate the biotin-binding properties of xenavidin - it binds biotin with high affinity though less tightly than do chicken avidin and bacterial streptavidin. X-ray crystallography revealed structural conservation around the ligand-binding site, while some of the loop regions have a unique design. The location of structural water molecules at the entrance and/or within the ligand-binding site may have a role in determining the characteristic biotin-binding properties of xenavidin. CONCLUSION: The novel data reported here provide information about the biochemically and structurally important determinants of biotin binding. This information may facilitate the discovery of novel tools for biotechnology.