* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Poster
Community fingerprinting wikipedia , lookup
Holliday junction wikipedia , lookup
List of types of proteins wikipedia , lookup
Genetic code wikipedia , lookup
Gel electrophoresis of nucleic acids wikipedia , lookup
Molecular evolution wikipedia , lookup
Molecular cloning wikipedia , lookup
Promoter (genetics) wikipedia , lookup
RNA interference wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Cre-Lox recombination wikipedia , lookup
DNA supercoil wikipedia , lookup
Real-time polymerase chain reaction wikipedia , lookup
Messenger RNA wikipedia , lookup
Non-coding DNA wikipedia , lookup
Silencer (genetics) wikipedia , lookup
Polyadenylation wikipedia , lookup
Biosynthesis wikipedia , lookup
RNA silencing wikipedia , lookup
RNA polymerase II holoenzyme wikipedia , lookup
Transcriptional regulation wikipedia , lookup
Gene expression wikipedia , lookup
Epitranscriptome wikipedia , lookup
Eukaryotic transcription wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
RNA Polymerase II St. Dominic Middle School Smart Team 18105 W. Capitol Drive, Brookfield ,WI 53045 This is RNA Polymerase II with 10 of its 12 subunits. This model shows how the DNA and RNA fit inside the enzyme for the transcription process. The DNA is cyan and the RNA is magenta. The bridge helix is the green structure in the picture. The bridge helix moves the DNA along to be transcribed. The black spot is the magnesium ion in the active site, which adds nucleotides to the growing RNA transcript. The clamp (orange) swings over the DNA to hold it down to be transcribed. Clamp RNA Polymerase II (Pol II), a major up-keeper of our cells, is found in the nucleus of all eukaryotic cells and is one of the most important enzymes in our body. Pol II has twelve protein subunits, which also makes it one of the largest molecules. Its function is to surround the DNA, unwind it, separate it into two strands, and use the DNA template strand to create a messenger RNA (mRNA) copy of a gene. These mRNA copies of genes are needed by the cell to make proteins to keep the cell healthy. The mRNAs are the templates used by ribosomes to link amino acids into long chains in the correct order to form all the different proteins in our bodies. In fact, RNA Pol II is so essential to life that when the poison, αamanitin, from the Death Cap mushroom attaches to RNA Pol II, death occurs within 10 days. The α-amanitin goes into the funnel portion of Pol II and inserts under the bridge helix. The poison is thought to limit the movement of the bridge helix and prevent a ratcheting movement that translocates the DNA template. When working properly, RNA Pol II can make RNA copies of DNA at speeds of about 3600 bases per minute. The α-amanitin slows this speed to 2 or 3 bases per minute. At this slow speed, RNA Polymerase II cannot do its job of making messenger RNA copies of our genes. Without mRNA molecules, the ribosomes cannot make the thousands of different proteins needed for life. Lid Zipper Rudder Chain A Chain A Chain A First Amino Acid Bridge Helix Last Amino Acid Magnesium Ion DNA Template RNA Transcript Chain A is the largest subunit of RNA Polymerase II. RNA Polymerase II makes a copy of the DNA, called messenger RNA, using the template strand. The DNA is unwound by RNA Pol II as it enters the enzyme. The clamp then closes over the DNA after it has been unwound. Movement of the bridge helix is thought to translocate the DNA so that nucleotides can be added to the RNA transcript. The rudder separates DNA and RNA from each other and the lid then guides mRNA and DNA template out of the enzyme. Finally, the zipper joins the DNA template strand to the non-template strand. Students: Sam Andreski, Julie Armstrong, Greg Cigich, Andrew Cobb, Kevin Drees, Mark Engel, Matt Geisinger, Joe Heckes, Patrick Jordan, Ryan Kohl, Kevin Koprowski, Michael Moakley, Rachael Reit, Tara Robey, Andrew Ruka, Michael Russell, Lauren Schmidt, Tyler Sherman, Paige Siehr Teacher: Donna LaFlamme Scientist Mentor: Dr. Vaughn Jackson, Medical College of Wisconsin RNA Polymerase II Coding Strand Double stranded DNA A T G T C T A G A T A G A T G T C T A G A T A G T A C A G A T C T A T C A U G U C U T A C A G A T C T A T Messenger RNA C Template Strand Our three-dimensional model of RNA Polymerase II was made by the Z-Corp printer. The Z-Corp printer is a printer that can print out threeA T G T C T A G A T A G dimensional designs, in millions of colors, from programs like T A C A G A T C T A T C RasMol. RasMol is a program that can be used to view structure files deposited by This is the process of transcription. The RNA Polymerase II (green) comes and separates the strands of scientists in the Protein Data Bank. The Z-Corp DNA. It then adds the nucleotide bases A, U, C, or G that compliment the template strand of DNA to prints in three dimensions by using layers of plaster make messenger RNA. When the RNA Pol II is finished, the mRNA copy floats away and the DNA gets instead of paper. To make the model, the printer zipped back together. The mRNA floats out into the cytoplasm to attach to a ribosome and be translated keeps adding layers of plaster from a moving boom. into a protein. The boom then repeatedly adds color and glue to areas on the surface indicated by a script file. Supported by the National Institutes of Health (NIH) – National Center for Research Resources Science Education Partnership Partnership Award (NCRR(NCRR-SEPA) A U G U C U A G A U A G Primary Citation: Structural Basis of Transcription: An RNA Polymerase II Elongation Complex at 3.3 Angstrom Resolution, Averell L. Gnatt, Patrick Cramer, Jianhua Fu, David A. Bushnell, Roger D. Kornberg, Science, Volume 292, page 1876 This figure was adapted from the article Structural Basis of Transcription: α-Amanitin-RNA Polymerase II Cocrystal at 2.8 angstrom resolution, David A. Bushnell, Patrick Cramer, and Roger D. Kornberg, PNAS, online Jan. 22, 2002