A mechanism of macroscopic (amorphous) aggregation of the tobacco mosaic virus coat protein.
To gain more insight into the mechanisms of heating-induced irreversible macroscopic aggregation of the tobacco mosaic virus (TMV) coat protein (CP), the effects of pH and ionic strength on this process were studied using turbidimetry, CD spectroscopy, and fluorescence spectroscopy. At 42 degrees C, the TMV CP passed very rapidly (in less than 15s) into a slightly unfolded conformation, presumably because heating disordered a segment of the subunit where the so-called hydrophobic girdle of the molecule resides. We suppose that the amino acid residues of this girdle are responsible for the aberrant hydrophobic interactions between subunits that initiate macroscopic protein aggregation. Its rate increased by several thousands of times as the phosphate buffer molarity was varied from 20 to 70 mM, suggesting that neutralization of strong repulsive electrostatic interactions of TMV CP molecules at high ionic strengths is a prerequisite for amorphous aggregation of this protein.
Rafikova
Elvira R
ER
A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 11999 Moscow, Russia.
Kurganov
Boris I
BI
Arutyunyan
Alexander M
AM
Kust
Stanislav V
SV
Drachev
Vladimir A
VA
Dobrov
Evgeny N
EN
D036022:Capsid Proteins / Q000737:chemistry* / Q000378:metabolism; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D018551:Solanum lycopersicum / Q000821:virology; D008958:Models, Molecular; D009029:Mosaic Viruses / Q000302:isolation & purification; D009994:Osmolar Concentration; D017863:Potexvirus / Q000302:isolation & purification; D011485:Protein Binding; D011487:Protein Conformation; D011489:Protein Denaturation; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D014027:Tobacco Mosaic Virus / Q000302:isolation & purification
D036022:Capsid Proteins; C009496:H protein, Tobacco mosaic virus