This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1rme
From Proteopedia
| Line 4: | Line 4: | ||
|PDB= 1rme |SIZE=350|CAPTION= <scene name='initialview01'>1rme</scene> | |PDB= 1rme |SIZE=350|CAPTION= <scene name='initialview01'>1rme</scene> | ||
|SITE= | |SITE= | ||
| - | |LIGAND= | + | |LIGAND= <scene name='pdbligand=5CM:5-METHYL-2'-DEOXY-CYTIDINE-5'-MONOPHOSPHATE'>5CM</scene>, <scene name='pdbligand=DC:2'-DEOXYCYTIDINE-5'-MONOPHOSPHATE'>DC</scene>, <scene name='pdbligand=DT:THYMIDINE-5'-MONOPHOSPHATE'>DT</scene> |
|ACTIVITY= | |ACTIVITY= | ||
|GENE= | |GENE= | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY= | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1rme FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1rme OCA], [http://www.ebi.ac.uk/pdbsum/1rme PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1rme RCSB]</span> | ||
}} | }} | ||
| Line 27: | Line 30: | ||
[[Category: tetramer]] | [[Category: tetramer]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 23:30:06 2008'' |
Revision as of 20:30, 30 March 2008
| |||||||
| Ligands: | , , | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
DNA (5'-D(5MCP*CP*TP*CP*C)-3') TETRAMER, NMR, 1 STRUCTURE
Overview
At slightly acidic pH, protonation of C-rich oligomers results in the formation of a four-stranded structure composed of two parallel duplexes in a head to tail orientation with their hemi-protonated C.C+ pairs intercalated in a so-called i-motif. In all cases reported previously the duplexes are identical. The tetramer formed by the d(5mCCTCC) oligomer is different. The structure is computed on the basis of 55 inter-residue distances derived from NOESY cross-peaks measured at short mixing times. It consists of two intercalated non-equivalent symmetrical duplexes. The base stacking order is C5* C1 C4* C2 (T3*) T3 C2* C4 C1* C5, but the thymidine bases (T3*) of one duplex are looped out and lie in the wide grooves of the tetramer. The thymidine bases T3 stack as a symmetrical T.T pair between the sequentially adjacent C2.C2+ pair and the C2*.C2*+ pair of the other duplex. Numerous exchange cross-peaks provide evidence for duplex interconversion. The interconversion rate is 1.4 s-1 at 0 degree C and the activation energy is 94 kJ/mol. The opening of the T3.T3 pair, the closing of the T3*.T3 pair, and the opening of the C2*.C2*+ pair occur simultaneously with the duplex interconversion. This suggests that the concerted opening and closing of the thymidine bases drive the duplex interconversion. Opening of the C4.C4+ and C4*.C4*+ pairs, and dissociation of the tetramer are not part of the interconversion since they occur at much slower rates. Duplex interconversion within the [d(5mCCTCC)]4 tetramer provides the first structural and kinetics characterization of broken symmetry in a biopolymer. The tetramer formed by d(5mCCUCC) adopts a similar structure, but the rate of duplex interconversion is faster: 40 s-1 at 0 degree C. At 32 degrees C, interconversion is fast on the NMR time scale.
About this Structure
1RME is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Structure and conversion kinetics of a bi-stable DNA i-motif: broken symmetry in the [d(5mCCTCC)]4 tetramer., Nonin S, Leroy JL, J Mol Biol. 1996 Aug 23;261(3):399-414. PMID:8780782
Page seeded by OCA on Sun Mar 30 23:30:06 2008
