Angewandte Chemie International Edition
© WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
For full article and contact information, see Angew. Chem. Int. Ed. 2001, 40 (3), 541-544
New Ways to Identify Viruses?
of intact viruses
You've just gotten over your last cold and you're already succumbing to the next wave of infection. Shouldn't you be immune? Tiny differences in the outer form of viruses are enough to keep them hidden from the immune system. The AIDS virus has been especially insidious in using continuous change to give the immune system the slip. These reasons alone justify the search for new methods of characterizing viruses. While mass spectrometry has already been used in viral research, researchers in California report new results; they have now been able to carry out mass spectrometric examination of entire intact viruses.
Well established in analytical chemistry research, mass spectrometry has recently been moving into biochemistry and medical diagnosis. In a mass spectrometric analysis, the molecules are ionized, separated and detected according to their mass. However, the high mass of virus particles (millions of Daltons) overtaxes current instruments. Henry Benner, Gary Siuzdak and their colleagues found a trick to overcome this problem. They chose to use the still relatively young method of charge-detection mass spectrometry, which allowed them to simultaneously determine both the charge and the mass-to-charge ratio of individual particles. Using these measurements, the mass of the entire virus particle can be measured.
Another remarkable finding is that viruses can survive the mild ionization conditions. They remain intact and infectious - remarkable given that the individual building blocks are not chemically bound together. Viruses consist of a protein coating and a DNA molecule that contains the genetic information. The protein shell is made up of hundreds or thousands of identical copies of a single coating protein.
"These measurements could allow us to study virus/antibody interactions or even the receptors from their host cells," explains Siuzdak. "At the same time the mass of the viruses could provide valuable information about different viral subpopulations."