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The P4-P6 domain of the
Tetrahymena thermophila self-splicing group I intron. Ball and stick view at
left. Special interest areas hilighted in animation below. |
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The P4-P6 domain of the
Tetrahymena thermophila self-splicing group I intron molecular model was
scripted by Mac/PC Molecule in .mcm format, which is a variation of the
Brookhaven .PDB file format from which it was created. The scripted .mcm files
have specially selected views and annotation. We have included some of the
information as examples of the annotated scripting of this molecule to give the
viewer an idea of the kind of information included in pre-scripted files and of
the sort of information they would be able to include in presentations of
molecules with Mac/PC Molecule by utilizing its scripting function were they to
create the scripted file themselves.
Tetrahymena thermophila is the
organism from which the molecule for this study was taken. The term, intron is
defined below on this page for the viewer of this page.
A portion of the
scripted annotation describes the molecule as:
" a 160 nucleotide
RNA with a sharp bend such that stacked helices of the conserved core pack
adjacent to helices of a neighboring region.
As noted in the abstract of
this study, 'Two specific long-range interactions clamp the two halves of the
domain together: a two-Mg2+-coordinated adenosine rich corkscrew plugs into the
minor groove of a helix, and a GAAA hairpin loop binds to a conserved
11-nucleotide internal loop...
The structure indicates the extent of RNA
packing required for the function of large ribozymes, the spliceosome, and the
ribosome.'
Coordinates courtesy of Jennifer Doudna."
The
abstract of the study done on this molecule is also referenced in the
annotation:
'Crystal Structure of a Group I Ribozyme Domain: Principles of
RNA Packing' by J.H. Cate, A.R. Gooding, E. Podell, K, Zhou, B.L. Golden, C.E.
Kundrot, T.R. Cech, and J.A. Doudna, Science 273, 1678-1685 (1996)." |
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We of course looked up the definition of , "intron,"
at the Genomics Lexicon.
Definition of Intron.
Intron: a length of DNA which is interspersed among
the protein-coding sequences (exons) in a gene. Introns are transcribed (see
transcription) into mRNA but are then cut out of the mRNA sequence before
protein synthesis occurs. See splicing.
definition source: The Genomics Lexicon
http://genomics.phrma.org/
One should probably also consult the Genomics Lexicon
to be sure of the meaning of the terms, "spliceozyme," "ribozyme," and
"ribosome."
This would give a clearer understanding of the
significance of the visual representation of this molecule and how its
structure, as depicted in the scripted file for the molecular model, relates to
transcription which is the process in which it is involved.
Why, one wonders, would a cell waste its time and
space with DNA code sequences which are read as RNA and then just cut them out
and not use them for transcription and synthesis of proteins. |
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About The Genomics Lexicon:
It is a joint project of the Pharmaceutical Research
and Manufacturers of America (PhRMA)http://www.phrma.org/ and the Foundation for
Genetic Medicine, Inc. (FGM),http://www.geneticmedicine.org/ is a
searchable database of terms and definitions.
PhRMA and FGM offer free access to the Lexicon in
order to help to educate the public, facilitate informed policy discussions,
and enable precise understanding and communication related to genetic medicine.
FGM and PhRMA will operate the Lexicon in coordination
with an interdisciplinary Editorial Advisory Board comprised of members of
FGM's International Board of Advisors and other opinion leaders from relevant
fields.
To recommend a new term, definition, and/or a need for
a new term and definition in the Genomics Lexicon, please E-mail your
suggestion(s) to lexicon@reston.com. We don't really have any suggestions
at this time. We are still trying to figure out the difference between a
self-splicing intron and a non-self-splicing intron ..... Hmmm..
Could it be
that one intron splices itself and the other doesn't?
Well, you know that
the PhRMA and the FGM are there in order to help to educate Buddy Q
Public, facilitate informed policy discussions, and enable precise
understanding and communication related to genetic medicine. |
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