1mdg

[[Image:1mdg.gif|left|200px]]<br /><applet load="1mdg" size="450" color="white" frame="true" align="right" spinBox="true"

caption="1mdg, resolution 1.50&Aring;" />

'''An Alternating Antiparallel Octaplex in an RNA Crystal Structure'''<br />

==Overview==

Multistranded helical structures in nucleic acids play various functions, in biological processes. Here we report the crystal structure of a, hexamer, rU(BrdG)r(AGGU),at 1.5 A resolution containing a structural, complex of an alternating antiparallel eight-stranded helical fragment, that is sandwiched in two tetraplexes. The octaplex is formed by groove, binding interaction and base tetrad intercalation between two tetraplexes., Two different forms of octaplexes have been proposed, which display, different properties in interaction with proteins and nucleic acids., Adenines form a base tetrad in the novel N6-H em leader N3 conformation, and further interact with uridines to form an adenine-uridine octad in the, reverse Hoogsteen pairing scheme. The conformational flexibility of, adenine tetrad indicates that it can optimize its conformation in, different interactions.

 

==About this Structure==

1MDG is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ] with NA and NCO as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1MDG OCA].

 

==Reference==

An eight-stranded helical fragment in RNA crystal structure: implications for tetraplex interaction., Pan B, Xiong Y, Shi K, Sundaralingam M, Structure. 2003 Jul;11(7):825-31. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=12842045 12842045]

[[Category: Protein complex]]

[[Category: Pan, B.C.]]

[[Category: Shi, K.]]

[[Category: Sundaralingam, M.]]

[[Category: Xiong, Y.]]

[[Category: NCO]]

[[Category: base octads]]

[[Category: base tetrads]]

[[Category: rna]]

[[Category: tetraplex]]