1k2g

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Structural basis for the 3'-terminal guanosine recognition by the group I intron

Overview

In the second step of the two consecutive transesterifications of the, self-splicing reaction of the group I intron, the conserved guanosine at, the 3' terminus of the intron (omegaG) binds to the guanosine-binding site, (GBS) in the intron. In the present study, we designed a 22-nt model RNA, (GBS/omegaG) including the GBS and omegaG from the Tetrahymena group I, intron, and determined the solution structure by NMR methods. In this, structure, omegaG is recognized by the formation of a base triple with the, G264 x C311 base pair, and this recognition is stabilized by the stacking, interaction between omegaG and C262. The bulged structure at A263 causes a, large helical twist angle (40 +/- 80) between the G264 x C311 and C262 x, G312 base pairs. We named this type of binding pocket with a bulge and a, large twist, formed on the major groove, a "Bulge-and-Twist" (BT) pocket., With another twist angle between the C262 x G312 and G413 x C313 base, pairs (45 +/- 100), the axis of GBS/omegaG is kinked at the GBS region., This kinked axis superimposes well on that of the corresponding region in, the structure model built on a 5.0 A resolution electron density map, (Golden et al., Science, 1998, 282:345-358). This compact structure of the, GBS is also consistent with previous biochemical studies on group I, introns. The BT pockets are also found in the arginine-binding site of the, HIV-TAR RNA, and within the 16S rRNA and the 23S rRNA.

About this Structure

1K2G is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.

Reference

Solution structure of an RNA fragment with the P7/P9.0 region and the 3'-terminal guanosine of the tetrahymena group I intron., Kitamura A, Muto Y, Watanabe S, Kim I, Ito T, Nishiya Y, Sakamoto K, Ohtsuki T, Kawai G, Watanabe K, Hosono K, Takaku H, Katoh E, Yamazaki T, Inoue T, Yokoyama S, RNA. 2002 Apr;8(4):440-51. PMID:11991639

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