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2002
LSU-HHMI Summer Undergraduate Research Program |
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 Abimbola
Sokunbi (Anne Grove, LSU Dept. of Biological Sciences)
Does Size Really Matter?
DNA structure can be extensively manipulated by proteins; these
proteins are of great significance in biology. In this study,
HU protein, a histone-like DNA binding protein obtained from
the hyperthermophilic bacterium, Thermatoga maritima, was explored
in its ability to cyclize DNA. HU belongs to a family of proteins
that introduces sharp bends into DNA and acts as accessory factors
which can facilitate the interaction of certain proteins to
specific binding sites. It has been proposed that HU exerts
its effect by contributing flexibility to different DNA binding
sites. Cyclization of DNA in the presence of proteins that bend
DNA should be enhanced. In this experiment, HU protein’s
effect on varying lengths of DNA was observed. The required
DNAs were isolated using restriction enzymes to excise desired
DNA fragments of specific length, ranging from 88-136bp, from
a pET5a plasmid. Gel electrophoresis and kinetic studies were
used to explore DNA cyclization of short linear DNA fragments
in the presence or absence of HU proteins. It is shown that
HU increases the cyclization of the fragments that were examined,
particularly the 105bp and 136bp. HU also enables the formation
of dimers in shorter DNA fragments, such as 88bp.
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