2. DNA FIXERS
This year Nobel Prize in chemistry was awarded to three scientists
whose research helps to explain how human beings continue to thrive
despite an invisible disadvantage---their totally unstable DNA
Human DNA can damaged by sunlight (u v radiations) ,environmental
toxins, carcinogenic substances( like those in cigarette smoke) and
various other factors. But even if people aren’t exposed to these harms,
their DNA is still unstable, as cell genomes undergo spontaneous
3. changes many times every day. In some cases, the constant division of
cells inside the body can go haywire, resulting defective copies of DNA.
Tomas Lindal, an emeritus scientist at the Francis Crick Institute in the
United Kingdom, was one of the first scientists to ask an important
question about DNA:”How stable it really?”In the 1970s , most
scientists thought the answer to this question was straight forward—
DNA is really stable. If it weren’t stable, complex life on Earth (including
human beings) would never have evolved in the first place.
But by experimenting with RNA(DNA’s
cousin) and, eventually, with DNA itself, Lindahl came to conclude that
DNA isn’t stable at all. In fact , it’s constantly decaying. But he also
discovered that there’s a very important molecular mechanism at work
that keeps DNA from collapsing completely: base excision repair , in
which special enzymes remove damage in DNA.
Lindah’ls breakthrough finding opened a
whole new field of research into other ways that cells repair DNA. Aziz
Scancar, a professor of biochemistry and biophysics at the University of
North Carolina School of Medicine, discovered how cells repair DNA
that’s damaged by UV radiation. This molecular process, has led to a
better understanding of why some people develop “skin cancer”-their
nucleotide excision repair system is defective.
4. Paul Mondrich, aprofessor of biochemistry at Duke
University in North Carolina, discovered yet another molecular repair
system called mismatched repair. During cell division, DNA replication
mistakes can be made , leading to mismatched nucleotides( the pairs of
bases that make up the rungs of the DNA “ladder”).These mismatches
can lead to all kinds of cellular problems if left uncorrected(including
certain cancers).But the mismatched pair mechanism corrects many of
these bad pairings between nucleotides, reducing the error frequency
during DNA replication by about a thousand times.
5.
6. The research conducted by all the three
Nobel recipients has advanced the field of chemistry, and will help in
the development of new tools for fighting diseases like cancer that
affect human cells, representatives with Nobel Foundation said in a
statement.
