From Proteopedia
(Difference between revisions)
proteopedia linkproteopedia link
|
|
| Line 1: |
Line 1: |
| - | [[Image:327d.gif|left|200px]] | + | {{Seed}} |
| | + | [[Image:327d.png|left|200px]] |
| | | | |
| | <!-- | | <!-- |
| Line 9: |
Line 10: |
| | {{STRUCTURE_327d| PDB=327d | SCENE= }} | | {{STRUCTURE_327d| PDB=327d | SCENE= }} |
| | | | |
| - | '''CRYSTAL STRUCTURES OF D(GM5CGM5CGCGCGC)'''
| + | ===CRYSTAL STRUCTURES OF D(GM5CGM5CGCGCGC)=== |
| | | | |
| | | | |
| - | ==Overview==
| + | <!-- |
| - | It is well known that methylation of alternating Py x Pu sequences potentiates the formation of Z-DNA. However, we have now observed that methylation of the alternating Z-DNA oligomer d(GCGCGCGCGC), which starts with a 5'-purine, unexpectedly stabilizes the A-DNA conformation. The double methyl derivative d(Gm5CGm5CGCGCGC), which crystallizes as duplex A-DNA in the hexagonal space group P6(1)22, a = b = 39.33 A and c = 77.93 A with one strand per asymmetric unit and six duplexes in the unit cell, refined to an R factor of 19.1 for 204 DNA atoms and 43 solvent molecules. This is the first report of a DNA sequence crystallized in both right and left-handed conformations, allowing structural comparisons not previously possible and, more importantly, this is the first time that methylation has been shown to potentiate the formation of A-DNA from a sequence known to crystallize as Z-DNA. From this study, ten base-pairs appear to be the critical length in determining the handedness of d(GC)n-type sequences in the crystalline state. Because methylation of nuclear DNA is linked to a number of cellular processes, including transcriptional inactivation, this study has important implications for the role of A-DNA in methylated regions of genomic DNA and, thus, in the regulation of gene expression. In this context, the structure of d(Gm5Cm5CGCGCGC) will be compared with that of the alternating A-DNA decamer d(GCACGCGTGC) and the alternating Z-DNA decamer d(GCGCGCGCGC) and discussed in terms of the forces that govern the handedness of duplex DNA oligomers.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_9236126}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 9236126 is the PubMed ID number. |
| | + | --> |
| | + | {{ABSTRACT_PUBMED_9236126}} |
| | | | |
| | ==About this Structure== | | ==About this Structure== |
| Line 26: |
Line 30: |
| | [[Category: Double helix]] | | [[Category: Double helix]] |
| | [[Category: Modified]] | | [[Category: Modified]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 20:15:53 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 12:53:35 2008'' |
Revision as of 09:53, 29 July 2008
Template:STRUCTURE 327d
CRYSTAL STRUCTURES OF D(GM5CGM5CGCGCGC)
Template:ABSTRACT PUBMED 9236126
About this Structure
Full crystallographic information is available from OCA.
Reference
Methylation of the Z-DNA decamer d(GC)5 potentiates the formation of A-DNA: crystal structure of d(Gm5CGm5CGCGCGC)., Tippin DB, Ramakrishnan B, Sundaralingam M, J Mol Biol. 1997 Jul 11;270(2):247-58. PMID:9236126
Page seeded by OCA on Tue Jul 29 12:53:35 2008
