PDBsum entry 4y6x

Structural protein

PDB id: 4y6x

Contents

Protein chains

144 a.a.

Waters ×190

PDB id:

4y6x

Name:

Structural protein

Title:

Structure of tobacco streak virus coat protein at 2.1 angstroms resolution (c2 crystal form)

Structure:

Coat protein. Chain: a, b, c. Fragment: unp residues 73-238. Engineered: yes

Source:

Tobacco streak virus. Organism_taxid: 12317. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.10Å R-factor: 0.181 R-free: 0.230

Authors:

A.Gulati,M.R.N.Murthy

Key ref:

A.Gulati et al. (2016). Structural studies on tobacco streak virus coat protein: Insights into the pleomorphic nature of ilarviruses. J Struct Biol, 193, 95. PubMed id: 26706030 DOI: 10.1016/j.jsb.2015.12.007

Date:

13-Feb-15 Release date: 20-Jan-16

Protein chains

A7UMQ4  (A7UMQ4_9BROM) -  Capsid protein from Tobacco streak virus

Seq: 238 a.a.

Struc: 144 a.a.

DOI no: 10.1016/j.jsb.2015.12.007

J Struct Biol 193:95 (2016)

PubMed id: 26706030

Structural studies on tobacco streak virus coat protein: Insights into the pleomorphic nature of ilarviruses.

A.Gulati, K.Alapati, A.Murthy, H.S.Savithri, M.R.Murthy.

ABSTRACT

Tobacco streak virus (TSV), the type member of Ilarvirus genus, is a major plant pathogen. TSV purified from infected plants consists of a ss-RNA genome encapsidated in spheroidal particles with diameters of 27, 30 and 33nm constructed from multiple copies of a single species of coat protein (CP) subunits. Apart from protecting the viral genome, CPs of ilarviruses play several key roles in the life cycle of these viruses. Unlike the related bromo and cucumoviruses, ilarvirus particles are labile and pleomorphic, which has posed difficulties in their crystallization and structure determination. In the current study, a truncated TSV-CP was crystallized in two distinct forms and their structures were determined at resolutions of 2.4Å and 2.1Å, respectively. The core of TSV CP was found to possess the canonical β-barrel jelly roll tertiary structure observed in several other viruses. Dimers of CP with swapped C-terminal arms (C-arm) were observed in both the crystal forms. The C-arm was found to be flexible and is likely to be responsible for the polymorphic and pleomorphic nature of TSV capsids. Consistent with this observation, mutations in the hinge region of the C-arm that reduce the flexibility resulted in the formation of more uniform particles. TSV CP was found to be structurally similar to that of Alfalfa mosaic virus (AMV) accounting for similar mechanism of genome activation in alfamo and ilar viruses. This communication represents the first report on the structure of the CP from an ilarvirus.