2rf4: Difference between revisions

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==Overview==

Synthesis of ribosomal RNA (rRNA) by RNA polymerase (Pol) I is the first, step in ribosome biogenesis and a regulatory switch in eukaryotic cell, growth. Here we report the 12 A cryo-electron microscopic structure for, the complete 14-subunit yeast Pol I, a homology model for the core enzyme, and the crystal structure of the subcomplex A14/43. In the resulting, hybrid structure of Pol I, A14/43, the clamp, and the dock domain, contribute to a unique surface interacting with promoter-specific, initiation factors. The Pol I-specific subunits A49 and A34.5 form a, heterodimer near the enzyme funnel that acts as a built-in elongation, factor and is related to the Pol II-associated factor TFIIF. In contrast, to Pol II, Pol I has a strong intrinsic 3'-RNA cleavage activity, which, requires the C-terminal domain of subunit A12.2 and, apparently, enables, ribosomal RNA proofreading and 3'-end trimming.

Synthesis of ribosomal RNA (rRNA) by RNA polymerase (Pol) I is the first step in ribosome biogenesis and a regulatory switch in eukaryotic cell growth. Here we report the 12 A cryo-electron microscopic structure for the complete 14-subunit yeast Pol I, a homology model for the core enzyme, and the crystal structure of the subcomplex A14/43. In the resulting hybrid structure of Pol I, A14/43, the clamp, and the dock domain contribute to a unique surface interacting with promoter-specific initiation factors. The Pol I-specific subunits A49 and A34.5 form a heterodimer near the enzyme funnel that acts as a built-in elongation factor and is related to the Pol II-associated factor TFIIF. In contrast to Pol II, Pol I has a strong intrinsic 3'-RNA cleavage activity, which requires the C-terminal domain of subunit A12.2 and, apparently, enables ribosomal RNA proofreading and 3'-end trimming.

==About this Structure==

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[[Category: Saccharomyces cerevisiae]]

[[Category: Cramer, P.]]

[[Category: Geiger, S.R.]]

[[Category: Geiger, S R.]]

[[Category: Kuhn, C.D.]]

[[Category: Kuhn, C D.]]

[[Category: ddrp]]

[[Category: dna-binding]]

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[[Category: transferase dna/rna]]

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@@ Line 4: / Line 4: @@
 ==Overview==
-Synthesis of ribosomal RNA (rRNA) by RNA polymerase (Pol) I is the first, step in ribosome biogenesis and a regulatory switch in eukaryotic cell, growth. Here we report the 12 A cryo-electron microscopic structure for, the complete 14-subunit yeast Pol I, a homology model for the core enzyme, and the crystal structure of the subcomplex A14/43. In the resulting, hybrid structure of Pol I, A14/43, the clamp, and the dock domain, contribute to a unique surface interacting with promoter-specific, initiation factors. The Pol I-specific subunits A49 and A34.5 form a, heterodimer near the enzyme funnel that acts as a built-in elongation, factor and is related to the Pol II-associated factor TFIIF. In contrast, to Pol II, Pol I has a strong intrinsic 3'-RNA cleavage activity, which, requires the C-terminal domain of subunit A12.2 and, apparently, enables, ribosomal RNA proofreading and 3'-end trimming.
+Synthesis of ribosomal RNA (rRNA) by RNA polymerase (Pol) I is the first step in ribosome biogenesis and a regulatory switch in eukaryotic cell growth. Here we report the 12 A cryo-electron microscopic structure for the complete 14-subunit yeast Pol I, a homology model for the core enzyme, and the crystal structure of the subcomplex A14/43. In the resulting hybrid structure of Pol I, A14/43, the clamp, and the dock domain contribute to a unique surface interacting with promoter-specific initiation factors. The Pol I-specific subunits A49 and A34.5 form a heterodimer near the enzyme funnel that acts as a built-in elongation factor and is related to the Pol II-associated factor TFIIF. In contrast to Pol II, Pol I has a strong intrinsic 3'-RNA cleavage activity, which requires the C-terminal domain of subunit A12.2 and, apparently, enables ribosomal RNA proofreading and 3'-end trimming.
 ==About this Structure==
@@ Line 15: / Line 15: @@
 [[Category: Saccharomyces cerevisiae]]
 [[Category: Cramer, P.]]
-[[Category: Geiger, S.R.]]
+[[Category: Geiger, S R.]]
-[[Category: Kuhn, C.D.]]
+[[Category: Kuhn, C D.]]
 [[Category: ddrp]]
 [[Category: dna-binding]]
@@ Line 34: / Line 34: @@
 [[Category: transferase dna/rna]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 11:08:54 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:46:47 2008''