Unusual frequencies of certain alternating purine‐pyrimidine runs in natural DNA sequences: relation to Z‐DNA

FEBS Letters

Konopka, Andrzej K.²  Jovin, Thomas M.²  Trifonov, Edward N.¹ 

[1] Department of Polymer Research, The Weizmann Institute of Science, Rehovot 76100, Israel;Max-Planck-lnstitut für biophysikalische Chemie, Abteilung Molekulare Biologie, Postfach 2841, D-3400 Göttingen, FRG

关键词: Left-handed DNA;    B-Z transition;    DNA loop;    S1 nuclease;   

DOI  :  10.1016/0014-5793(85)80769-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Prokaryotic, eukaryotic and mitochondrial DNA sequences of total Length 300000 nucleotides have been analyzed to find out whether stretches of alternating purines and pyrimidines are unusual in terms of occurrence, composition and base sequence. Alternating runs longer than 5 nucleotides are significantly underrepresented in the natural sequences as compared to random ones. Octanucleotides are the most deficient, occurring at only 60% of the frequency expected in random sequences. An unexpectedly high proportion of these octamers consists of alternating tetramers with the repeat structure (PuPyPuPy)₂or (PyPuPyPu)₂. DNA stretches containing such sequences can potentially form a Sl nuclease sensitive slippage (staggered loop) structure, which might serve as a locally unstacked intermediate in the B- to Z-DNA conformational transition.

【 授权许可】

Unknown