1TUT

J4/5 Loop from the Candida albicans and Candida dubliniensis Group I Introns

Summary for 1TUT

• Entry DOI: 10.2210/pdb1tut/pdb
• Descriptor: 5'-R(*GP*AP*GP*GP*AP*AP*GP*GP*CP*GP*A)-3', 5'-R(*UP*CP*GP*UP*UP*AP*AP*UP*CP*UP*C)-3' (2 entities in total)
• Functional Keywords: rna, internal loop, tandem mismatch, gu pairs, aa pairs
• Total number of polymer chains: 2
• Total formula weight: 7053.32

Authors

Znosko, B.M.,Kennedy, S.D.,Wille, P.C.,Krugh, T.R.,Turner, D.H. (deposition date: 2004-06-25, release date: 2004-12-28, Last modification date: 2024-05-22)

Primary citation

Znosko, B.M.,Kennedy, S.D.,Wille, P.C.,Krugh, T.R.,Turner, D.H.
Structural Features and Thermodynamics of the J4/5 Loop from the Candida albicans and Candida dubliniensis Group I Introns.
Biochemistry, 43:15822-15837, 2004

PubMed Abstract: The J4/5 loop of group I introns has tertiary interactions with the P1 helix that position the P1 substrate for the self-splicing reaction. The J4/5 loop of Candida albicans and Candida dubliniensis, 5'GAAGG3'/3'UAAUU5', potentially contains two A.A pairs flanked by one G.U pair on one side and two G.U pairs on the other side. Results from optical melting, nuclear magnetic resonance spectroscopy, and functional group substitution experiments with a mimic of the C. albicans and C. dubliniensis J4/5 loop are consistent with the adenosines forming tandem sheared A.A pairs with a cross-strand stack and only the G.U pair not adjacent to an A.A pair forming a static wobble G.U pair. The two G.U pairs adjacent to the tandem A.A pairs are likely in a dynamic equilibrium between multiple conformations. Although Co(NH(3))(6)(3+) stabilizes the loop by several kilocalories per mole at 37 degrees C, addition of Mg(2+) or Co(NH(3))(6)(3+) has no effect on the structure of the loop. The tandem G.U pairs provide a pocket of negative charge for Co(NH(3))(6)(3+) to bind. The results contribute to understanding the structure and dynamics of purine-rich internal loops and potential G.U pairs adjacent to internal loops.

PubMed: 15595837
DOI: 10.1021/bi049256y

Experimental method

SOLUTION NMR