Homology modelling and protein structure based functional analysis of five cucumovirus coat proteins

• Published in: Journal of molecular graphics & modelling 2006-03, Vol.24 (5), p.319-327
• Main Authors: Gellert, Akos, Salanki, Katalin, Naray-Szabo, Gabor, Balazs, Ervin
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Capsid Proteins - chemistry; Capsid Proteins - genetics; Capsid Proteins - metabolism; Cucumber mosaic virus; Cucumovirus; Cucumovirus - genetics; Cucumovirus - pathogenicity; Cytomegalovirus; Electrostatic potential analysis; Homology modelling; Hydrophobic and Hydrophilic Interactions; Models, Molecular; Molecular Sequence Data; Mutation; Peanut stunt virus; Phosphorylation; Phylogeny; Protein Conformation; Protein Structure, Secondary; Sequence analysis; Sequence Homology, Amino Acid; Static Electricity; Tomato aspermy virus; Viral Proteins - chemistry; Viral Proteins - genetics; Viral Proteins - metabolism; Virology
• ISSN: 1093-3263; 1873-4243
• DOI: 10.1016/j.jmgm.2005.09.015

Coat proteins (CP) of five cucumovirus isolates, Cucumber mosaic virus (CMV) strains R, M and Trk7, Tomato aspermy virus (TAV) strain P and Peanut stunt virus (PSV) strain Er, were constructed by homology modelling. The X-ray structure of the Fny-CMV CP subunit B was used as a template. Models of cucumovirus CPs were built by the MODELLER program. Model refinements were carried out using the Kollman molecular mechanical force field. Models were analyzed by the PROCHECK programs. Electrostatic potential calculations were applied to all models and functional site search was performed with the PROSITE software, a web based tool for searching biologically significant sites. Symptom determinants published up to the present were compared with the PROSITE hits in the light of 3D models and electrostatic information. In all cases, we analyzed the effect of mutations on the structure, electrostatic potential patterns and function of CPs, respectively. We found that high flexibility of the βE–αEF loop starting with the residue 129 is required, but it is not sufficient for the symptom appearance. Furthermore, phosphorylation of the CP is prospective to be important in the host response mechanism. All analyzed mutations were related to the modifications of the predicted phosphorylation sites. Based on our conclusions we predicted the infectivity of the examined viruses.