PDBsum entry: 1rfo

Viral protein

PDB id: 1rfo

Contents

Protein chains

27 a.a.

PDB id:

1rfo

Name:

Viral protein

Title:

Trimeric foldon of the t4 phagehead fibritin

Structure:

Whisker antigen control protein. Chain: a, b, c. Fragment: trimerization domain (residues 457-483). Engineered: yes

Source:

Enterobacteria phage t4. Organism_taxid: 10665. Gene: wac. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

NMR struc:

10 models

Authors:

S.Guthe,L.Kapinos,A.Moglich,S.Meier,T.Kiefhaber,S.Grzesiek

Key ref:

S.Güthe et al. (2004). Very fast folding and association of a trimerization domain from bacteriophage T4 fibritin. J Mol Biol, 337, 905-915. PubMed id: 15033360 DOI: 10.1016/j.jmb.2004.02.020

Date:

10-Nov-03 Release date: 30-Mar-04

Protein chains

P10104  (WAC_BPT4) -  Fibritin

Seq: 487 a.a.

Struc: 27 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

 Gene Ontology (GO) functional annotation 

• Biological process: oxidation-reduction process (1 term)
• Biochemical function: phosphogluconate dehydrogenase (decarboxylating) activity (1 term)

DOI no: 10.1016/j.jmb.2004.02.020

J Mol Biol 337:905-915 (2004)

PubMed id: 15033360

Very fast folding and association of a trimerization domain from bacteriophage T4 fibritin.

S.Güthe, L.Kapinos, A.Möglich, S.Meier, S.Grzesiek, T.Kiefhaber.

ABSTRACT

The foldon domain constitutes the C-terminal 30 amino acid residues of the trimeric protein fibritin from bacteriophage T4. Its function is to promote folding and trimerization of fibritin. We investigated structure, stability and folding mechanism of the isolated foldon domain. The domain folds into the same trimeric beta-propeller structure as in fibritin and undergoes a two-state unfolding transition from folded trimer to unfolded monomers. The folding kinetics involve several consecutive reactions. Structure formation in the region of the single beta-hairpin of each monomer occurs on the submillisecond timescale. This reaction is followed by two consecutive association steps with rate constants of 1.9(+/-0.5)x10(6)M(-1)s(-1) and 5.4(+/-0.3)x10(6)M(-1)s(-1) at 0.58 M GdmCl, respectively. This is similar to the fastest reported bimolecular association reactions for folding of dimeric proteins. At low concentrations of protein, folding shows apparent third-order kinetics. At high concentrations of protein, the reaction becomes almost independent of protein concentrations with a half-time of about 3 ms, indicating that a first-order folding step from a partially folded trimer to the native protein (k=210 +/- 20 s(-1)) becomes rate-limiting. Our results suggest that all steps on the folding/trimerization pathway of the foldon domain are evolutionarily optimized for rapid and specific initiation of trimer formation during fibritin assembly. The results further show that beta-hairpins allow efficient and rapid protein-protein interactions during folding.

Selected figure(s)

Figure 1.
Figure 1. A, Stereo view of a bundle of the 20 lowest-energy structures of the trimeric foldon domain determined by NMR spectroscopy. Each subunit is displayed in a different color. B, Side view of the foldon structure with the single Trp residues at position 20 of each chain highlighted in green and the two prolyl residues at positions 4 and 7 highlighted in red. C, Topology of the interactions of the three b-hairpins in the native foldon domain. The figures in A and B were prepared using the program MOLMOL[37.] and rendered with PovRay.

Figure 6.
Figure 6. Effect of total monomer concentration ([M][0]) on the half-time of the fast-refolding reaction of the foldon domain at 0.58 M GdmCl (pH 7.1), 20 °C. The continuous line represents a fit of the data between 0.5 µM and 4 µM to equation (3). The fit gives a slope of -2.06±0.05 indicating an apparent reaction order of 3 at low concentrations of protein.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2004, 337, 905-915) copyright 2004.

Figures were selected by the author.