Biology Reference
In-Depth Information
31
Another interesting application of variability plot is the analysis of amino
acid sequences of one of the surface glyco-proteins of HTV, gp120. The
gene coding for this protein mutates rapidly so that new mutant HIV can
avoid the antibodies produced by patients to bind the original virus.
Thousands of amino acid sequences of gp120 have been determined and
aligned. A variability plot for these sequences clearly identified several
segments of relatively higher frequencies of amino acid substitutions. One
of these segments, known as the V3-loop, appears distinct from the others.
It is this segment that protein and DNA vaccinations are under development
as discussed before.
In short, variability plot is one of the simple yet powerful methods of
analyzing aligned amino acid sequences of homologous proteins. It can
provide essential information about their structure and function relations at a
molecular level.
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