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Exploring Nucleic Acid Structure: Insights from DNA Conformations

Delve into the world of DNA structure and conformation, from base pairing to backbone conformation. Learn about the various forms of DNA and the evolving terminology for describing different structures. Dive into a comprehensive glossary of DNA structures from A to Z. This text provides a detailed overview of the fundamental aspects of DNA conformation, essential for understanding its role in genetics and molecular biology research.

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Exploring Nucleic Acid Structure: Insights from DNA Conformations

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  1. Nucleic Acid Structure & Conformation - Intro M.Bansal

  2. --Lehninger 5th Ed

  3. WC base-pairing Hoogsteen base-pairing

  4. The x-ray fibre diffraction pattern of sodium salt of DNA-B at 90% R.H.(Rosalind Franklin 1953)

  5. DNA facts: • Deoxyribose - Nucleic Acid • Base composition: • Erwin Chargaff • (A)=(T), (G)=(C) • X-ray pattern: • Rosalind Franklin • Structure: • James Watson & Francis Crick • - base pairing between • A-T and G-C • - double helical model with • 10 units per turn.

  6. aO3’-P-O5’-C5’ (g-) bP-O5’-C5’-C4’ (t) g O5’-C5’-C4’-C3’ (g+ ) d C5’-C4’-C3’-O3’ (2E) e C4’-C3’-O3’-P (t) z C3’-O3’-P-O5’ (g-) Backbone conformation

  7. The puckering of the ribose ring is described by the phase angle P, where (ν2+ν4)-(ν1+ν3) P = arctan -------------------------------- 2ν0[sin(π/5)+sin(2π/5)]

  8. 5’ 5’ 5’ B Z A

  9. Torsion Angles Corresponding to A, B, Z DNA Structures n 11 10 -6 h 2.56 3.3 7.2

  10. DNA structures from A to Z The various forms of DNA have been identified as A, B, C etc. In fact, a detailed inspection of the literature reveals that only the letters F, Q, U, V and Y are now available, to describe any new DNA structure that may appear in future.Itis also apparent that it may be more relevant to talk about the A, B or C type dinucleotide steps,since several recent structures show mixtures of various different geometries and a careful analysis is essential before identifying it as a ‘new structure’. A Glossary of DNA structures from A to Z A. Ghosh & M. Bansal , Acta Cryst D, vol 59 (Apr 2003)

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