Path: utzoo!attcan!uunet!husc6!mailrus!tut.cis.ohio-state.edu!unmvax!unm-la!lanl!beta!dd
From: dd@beta.lanl.gov (Dan Davison)
Newsgroups: sci.bio
Subject: Re: Chromosome Topology of the Human Genome
Summary: fitting lotsa DNA in a very,very small space
Message-ID: <23046@beta.lanl.gov>
Date: 23 Dec 88 01:52:51 GMT
References: <17231@dhw68k.cts.com>
Distribution: na
Organization: Los Alamos National Laboratory
Lines: 24

In article <17231@dhw68k.cts.com>, stein@dhw68k.cts.com (Rick Stein) writes:
> I'm curious to know why the DNA material is "stored" in this conformation
> as opposed to some other topology.  Presumably, there is some "glue protein"
> which forces the genetic material into this shape.  Does anyone know what
> they call this "glue?"


There is a problem in a chapter of the original Lehninger Biochemistry
text that will give you the flavor of the problem.  Leaving *lots* of
other problems aside, the DNA in a human cell if a single straight
strand would just about make it to the moon (if I am recalling the
problem correctly).  In any event, you have at least hundreds of miles
of relatively fragile "carbohydrate with nitrogenous contaminants" that
you must stuff into a nucleus that is (say) 10e-6 meters in diameter.

The "glue" is an assortment of proteins, the predominant ones called
"histones" which are among the most highly conserved proteins know. (For
example, cow and pea histone (H1?) have one or two differences while
their ancestors diverged at least 400 million years ago.
-- 
dan davison/theoretical biology/t-10 ms k710/los alamos national laboratory
los alamos, nm 875545/dd@lanl.gov (arpa)/dd@lanl.uucp(new)/..cmcl2!lanl!dd
'The true mark of intelligence is an unwillingness to fill in the many
gaps in our understanding with a set of irrational beliefs'(Keats,paraphrased)