Summary of Research Project Results under JSPS FY2001 "Research for the Future Program"

(1)Structure determination of RNA by NMR -- Structures of a 39-mer RNA corresponding to the dimerization initiation site of HIV-1 genomic RNA were determined in two types of conformations; kissing dimer and duplex dime. It was found that the two conformations are almost identical except for the region around the both ends of the self complement loop. Structure of a 29-mer RNA corresponding to the helix 6 of human SRP RNA was determined in the free hairpin form. The GGAG tetraloop in helix 6 adopts a similar conformation to that of GNRA tetraloop, suggesting that these tetraloops are included in an extensive new motif GNRR. Compared with the structure of helix 6 in complex with SRP19 determined previously, the GGAG tetraloop in the complex adopts a similar conformation to that of the free form, although the conformation is changed to a more open conformation upon SRP19 binding. NMR analysis of a 31-mer RNA corresponding a pseudoknot, PK1, of tmRNA revealed that the PK1 RNA is folded into a pseudoknot structure in the presence of Mg²⁺. Results of NMR analyses of PK1 mutants together with their biological activities indicates that trans-translation requires the pseudoknot structure stabilized by Mg²⁺ and specific residues G61 and G62 in loop 3. Structure of a 22-mer RNA corresponding to the P7/P9.0 region and the 3'-terminal guanosine of the Tetrahymena group I intron was also determined to find a new structural motif, BT-motif. (2) Structure determination of RNA by X-ray crystallography --Single crystals for RNAs corresponding to the dimerization initiation site of HIV-1 genomic RNA and the hammerhead ribozyme in a heterodimer form are finally obtained. Structure determinations are in progress. (3) RNA binding proteins -- RNA recognition mechanisms were revealed for the Drosophila Sxl protein and human U2AF protein by X-ray crystallography and NMR technique.

1.Research Institution		Chiba Institute of Technology

2.Research Area		Life Sciences

3.Research Field		Structure and Functional Control Mechanism of Biomolecules (Structural Biology and Functional Molecules)

4.Term of Project		FY 1997 ～ FY 2001

5.Project Number		97L00503

6.Title of Project		Structural Biology of RNA

Name	Institution,Department	Title of Position
Gota Kawai	Chiba Institute of Technology, Department of Industrial Chemistry	Associate Professor

Names	Institution,Department	Title of Position
Yutaka Muto	The University of Tokyo, Graduate School of Sciences	Lecturer
Akio Takenaka	Tokyo Institute of Technology, Graduate School of Bioscience and Biotechnology	Associate Professor

Summary of Research Project Results under JSPS FY2001"Research for the Future Program"

Summary of Research Project Results under JSPS FY2001
"Research for the Future Program"