PDBsum entry 1n8b

Viral protein

PDB id: 1n8b

Contents

Protein chains

328 a.a. *

Metals

_BR ×40

Waters ×278

* Residue conservation analysis

PDB id:

1n8b

Name:

Viral protein

Title:

Bacteriophage t4 baseplate structural protein gp8

Structure:

Baseplate structural protein gp8. Chain: a, b, c, d. Synonym: baseplate wedge protein 8. Engineered: yes

Source:

Enterobacteria phage t4. Organism_taxid: 10665. Gene: gene 8. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Biol. unit:

Dimer (from PQS)

Resolution:

2.90Å R-factor: 0.222 R-free: 0.300

Authors:

P.G.Leiman,M.M.Shneider,V.A.Kostyuchenko,P.R.Chipman, V.V.Mesyanzhinov,M.G.Rossmann

Key ref:

P.G.Leiman et al. (2003). Structure and location of gene product 8 in the bacteriophage T4 baseplate. J Mol Biol, 328, 821-833. PubMed id: 12729757 DOI: 10.1016/S0022-2836(03)00366-8

Date:

20-Nov-02 Release date: 10-Jun-03

Protein chains

P19062  (BP08_BPT4) -  Baseplate wedge protein gp8 from Enterobacteria phage T4

Seq: 334 a.a.

Struc: 328 a.a.

DOI no: 10.1016/S0022-2836(03)00366-8

J Mol Biol 328:821-833 (2003)

PubMed id: 12729757

Structure and location of gene product 8 in the bacteriophage T4 baseplate.

P.G.Leiman, M.M.Shneider, V.A.Kostyuchenko, P.R.Chipman, V.V.Mesyanzhinov, M.G.Rossmann.

ABSTRACT

Many bacteriophages, such as T4, T7, RB49, and phi29, have complex, sometimes multilayered, tails that facilitate an almost 100% success rate for the viral particles to infect host cells. In bacteriophage T4, there is a baseplate, which is a multiprotein assembly, at the distal end of the contractile tail. The baseplate communicates to the tail that the phage fibers have attached to the host cell, thereby initiating the infection process. Gene product 8 (gp8), whose amino acid sequence consists of 334 residues, is one of at least 16 different structural proteins that constitute the T4 baseplate and is the sixth baseplate protein whose structure has been determined. A 2.0A resolution X-ray structure of gp8 shows that the two-domain protein forms a dimer, in which each monomer consists of a three-layered beta-sandwich with two loops, each containing an alpha-helix at the opposite sides of the sandwich. The crystals of gp8 were produced in the presence of concentrated chloride and bromide ions, resulting in at least 11 halide-binding sites per monomer. Five halide sites, situated at the N termini of alpha-helices, have a protein environment observed in other halide-containing protein crystal structures. The computer programs EMfit and SITUS were used to determine the positions of six gp8 dimers within the 12A resolution cryo-electron microscopy image reconstruction of the baseplate-tail tube complex. The gp8 dimers were found to be located in the upper part of the baseplate outer rim. About 20% of the gp8 surface is involved in contacts with other baseplate proteins, presumed to be gp6, gp7, and gp10. With the structure determination of gp8, a total of 53% of the volume of the baseplate has now been interpreted in terms of its atomic structure.

Selected figure(s)

Figure 2.
Figure 2. A ribbon diagram of the gp8 dimer. Three orthogonal orientations are shown. The two monomers are colored red and blue. The blue monomer at the top has the same orientation as the monomer in Figure 1.

Figure 4.
Figure 4. The k = 1808 rotation functions calculated using the 10 -- 3 A š resolution data of crystal form I (left) and crystal form II (right). The maps are scaled so that the highest peak has a value of 1000.0 and contoured starting from a level of 50.0 with intervals of 50.0. The orthogonalization convention and the polar angles are as defined by the PDB. For crystal form I, the peaks are labeled as follows: A , 2-fold screw axis (height of 9.5s); B , 2-fold axis (8.0s); C , two parallel dimer 2-folds (7.9s). For crystal form II: A00, 2-fold screw (13.0s); B00 , 2-fold (7.8s); C00 , two parallel dimer 2-folds (8.2s).

The above figures are reprinted by permission from Elsevier: J Mol Biol (2003, 328, 821-833) copyright 2003.

Figures were selected by an automated process.