'''STRUCTURE OF A DNA ANALOG OF THE PRIMER FOR HIV-1 RT SECOND STRAND SYNTHESIS'''
===STRUCTURE OF A DNA ANALOG OF THE PRIMER FOR HIV-1 RT SECOND STRAND SYNTHESIS===
==Overview==
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The non-self-complementary DNA decamer C-A-A-A-G-A-A-A-A-G/C-T-T-T-T-C-T-T-T-G is a DNA/DNA analogue of a portion of the polypurine tract or PPT, which is a RNA/DNA hybrid that serves as a primer for synthesis of the (+) DNA strand by HIV reverse transcriptase (RT), and which is not digested by the RNase H domain of reverse transcriptase following (-) strand synthesis. The same unusual conformation that eludes RNase H, thought to be a change in width of minor groove, may also be responsible for the inhibition of HIV RT by minor groove binding drugs such as distamycin and their bis-linked derivatives. The present X-ray crystal structure of this DNA decamer exhibits the usual properties of A-tract B-DNA under biologically relevant conditions: large propeller twist of base-pairs, narrowed minor groove, and a straight helix axis. Groove narrowing is fully developed in the A-A-A-A region, but not in the A-A-A region, which previous investigators have proposed as being too short to exhibit typical A-tract properties. The RNA/DNA hybrid produced by HIV reverse transcriptase during (-) strand synthesis presumably forms a "heteromerous" or H-helix with narrower minor groove than an A-helical RNA/RNA duplex. If the narrowing of minor groove in A-tract H-helices is comparable to that seen in A-tract B-helices, then the narrowed minor groove of the polypurine tract could make the second primer site both (1) impervious to RNase H digestion, and (2) susceptible to inhibition by minor groove binding drugs.
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==About this Structure==
==About this Structure==
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[[Category: B-dna]]
[[Category: B-dna]]
[[Category: Double helix]]
[[Category: Double helix]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 08:42:33 2008''
Revision as of 05:42, 29 July 2008
This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.
Full crystallographic information is available from OCA.
Reference
Structure of a DNA analog of the primer for HIV-1 RT second strand synthesis., Han GW, Kopka ML, Cascio D, Grzeskowiak K, Dickerson RE, J Mol Biol. 1997 Jun 27;269(5):811-26. PMID:9223643
