1ikk
From Proteopedia
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| - | [[Image:1ikk.gif|left|200px]] | + | [[Image:1ikk.gif|left|200px]] |
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| - | '''Intrinsic Bending and Deformability at the T-A step of CCTTTAAAGG: A Comparative Analysis of T-A and A-T steps within A-tracts''' | + | {{Structure |
| + | |PDB= 1ikk |SIZE=350|CAPTION= <scene name='initialview01'>1ikk</scene>, resolution 1.60Å | ||
| + | |SITE= | ||
| + | |LIGAND= <scene name='pdbligand=MG:MAGNESIUM ION'>MG</scene> | ||
| + | |ACTIVITY= | ||
| + | |GENE= | ||
| + | }} | ||
| + | |||
| + | '''Intrinsic Bending and Deformability at the T-A step of CCTTTAAAGG: A Comparative Analysis of T-A and A-T steps within A-tracts''' | ||
| + | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1IKK is a [ | + | 1IKK is a [[Protein complex]] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IKK OCA]. |
==Reference== | ==Reference== | ||
| - | Intrinsic bending and deformability at the T-A step of CCTTTAAAGG: a comparative analysis of T-A and A-T steps within A-tracts., Mack DR, Chiu TK, Dickerson RE, J Mol Biol. 2001 Oct 5;312(5):1037-49. PMID:[http:// | + | Intrinsic bending and deformability at the T-A step of CCTTTAAAGG: a comparative analysis of T-A and A-T steps within A-tracts., Mack DR, Chiu TK, Dickerson RE, J Mol Biol. 2001 Oct 5;312(5):1037-49. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/11580248 11580248] |
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Chiu, T K.]] | [[Category: Chiu, T K.]] | ||
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[[Category: b-dna double helix]] | [[Category: b-dna double helix]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 11:51:34 2008'' |
Revision as of 09:51, 20 March 2008
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| Coordinates: | save as pdb, mmCIF, xml | ||||||
Intrinsic Bending and Deformability at the T-A step of CCTTTAAAGG: A Comparative Analysis of T-A and A-T steps within A-tracts
Overview
Introduction of a T-A or pyrimidine-purine step into a straight and rigid A-tract can cause a positive roll deformation that kinks the DNA helix at that step. In CCTTTAAAGG, the central T-A step has an 8.6 degrees bend toward the major groove. We report the structural analysis of CCTTTAAAGG and a comparison with 25 other representative crystal structures from the NDB containing at least four consecutive A or T bases. On average, more local bending occurs at the disruptive T-A step (8.21 degrees ) than at an A-T step (5.71 degrees ). In addition, A-tracts containing an A-T step are more bent than are pure A-tracts, and hence A-A and A-T steps are not equivalent. All T-A steps examined exhibit positive roll, bending towards the major groove, while A-T steps display negative roll and bend slightly towards the minor groove. This illustrates how inherent negative and positive roll are, respectively, at A-T and T-A steps within A-tracts. T-A steps are more deformable, showing larger and more variable deformations of minor groove width, rise, cup, twist, and buckle. Standard deviations of twist, rise, and cup for T-A steps are 6.66 degrees, 0.55 A, and 15.90 degrees, versus 2.28 degrees, 0.21 A, and 2.99 degrees for A-T steps. Packing constraints determine which local values of these helical parameters an individual T-A step will adopt. For instance, with CCTTTAAAGG and three isomorphous structures, CGATTAATCG, CGATATATCG, and CGATCGATCG, crystal packing forces lead to a series of correlated changes: widened minor groove, large slide, low twist, and large rise. The difference in helical parameters between A-T steps lying within A-tracts, versus A-T steps within alternating AT sequences, demonstrates the importance of neighboring steps on the conformation of a given dinucleotide step.
About this Structure
1IKK is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Intrinsic bending and deformability at the T-A step of CCTTTAAAGG: a comparative analysis of T-A and A-T steps within A-tracts., Mack DR, Chiu TK, Dickerson RE, J Mol Biol. 2001 Oct 5;312(5):1037-49. PMID:11580248
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