Control of branch-site choice by a group II intron

Citation
Vt. Chu et al., Control of branch-site choice by a group II intron, EMBO J, 20(23), 2001, pp. 6866-6876
Citations number
48
Categorie Soggetti
Molecular Biology & Genetics
Journal title
EMBO JOURNAL
ISSN journal
02614189 → ACNP
Volume
20
Issue
23
Year of publication
2001
Pages
6866 - 6876
Database
ISI
SICI code
0261-4189(200112)20:23<6866:COBCBA>2.0.ZU;2-A
Abstract
The branch site of group II introns is typically a bulged adenosine near th e 3'-end of intron domain 6. The branch site is chosen with extraordinarily high fidelity, even when the adenosine is mutated to other bases or if the typically bulged adenosine is paired. Given these facts, it has been diffi cult to discern the mechanism by which the proper branch site is chosen. In order to dissect the determinants for branch-point recognition, new mutati ons were introduced in the vicinity of the branch site and surrounding doma ins. Single mutations did not alter the high fidelity for proper branch-sit e selection. However, several combinations of mutations moved the branch si te systematically to new positions along the domain 6 stem. Analysis of tho se mutants, together with a new alignment of domain 5 and domain 6 sequence s, reveals a set of structural determinants that appear to govern branch-si te selection by group II introns.