A biochemical and crystallographic study of tobacco streak virus, a virus containing a zinc finger
Abstract
Tobacco streak virus (TSV) is the type member of the ilarvirus family. This positive single stranded RNA containing virus possesses the ability to produce nucleoprotein particles of differing sizes with just a single type of capsid protein. A characteristic that is unique to ilar viruses is the requirement for the capsid protein during virus replication. We have shown that this requirement for infectivity is correlated with zinc content in alfalfa mosaic virus, which is presumably due to the protein motif found in the caspid protein called a zinc finger. The consensus cysteine, histidine sequence is present in the amino terminus which is inside the virion. Removal of this amino terminus with a lysine specific protease has allowed for biochemical and biophysical characterization of metal and RNA binding capabilities. The capsid protein of TSV when treated with trypsin loses 87 amino terminal residues and produces a soluble dimer of 35,000 molecular weight. This resultant polypeptide has been successfully crystallized into two crystal forms suitable for x-ray diffraction studies. A complete native data set at 6.0 A resolution was collected for the hexagonal crystal form which belongs to the space group P6$\sb2$ or P6$\sb4$. Three heavy derivatized crystal data sets were also collected for this same crystal form. A self rotation function indicates that the position of the molecules is consistent with dimeric forms. The second crystal form of TSV trypsinized capsid protein diffracts to 2.2 A resolution and is of overall higher quality.
Degree
Ph.D.
Advisors
Johnson, Purdue University.
Subject Area
Biophysics|Molecular biology
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.