期刊
JOURNAL OF MOLECULAR BIOLOGY
卷 329, 期 2, 页码 253-269出版社
ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD
DOI: 10.1016/S0022-2836(03)00447-9
关键词
endonuclease; structure; isoschizomer; homing; specificity
资金
- NCI NIH HHS [T32 CA80416, CA88942] Funding Source: Medline
- NIGMS NIH HHS [GM49857] Funding Source: Medline
Homing endonucleases are highly specific catalysts of DNA strand breaks that induce the transposition of mobile intervening sequences containing the endonuclease open reading frame. These enzymes recognize long DNA targets while tolerating individual sequence polymorphisms within those sites. Sequences of the homing endonucleases themselves diversify to a great extent after founding intron invasion events, generating highly divergent enzymes that recognize similar target sequences. Here, we visualize the mechanism of flexible DNA recognition and the pattern of structural divergence displayed by two homing endonuclease isoschizomers. We determined structures of I-CreI bound to two DNA target sites that differ at eight of 22 base-pairs, and the structure of an isoschizomer, I-Mso I, bound to a nearly identical DNA target site. This study illustrates several principles governing promiscuous base-pair recognition by DNA-binding proteins, and demonstrates that the isoschizomers display strikingly different protein/DNA contacts. The structures allow us to determine the information content at individual positions in the binding site as a function of the distribution of direct and water-mediated contacts to nucleotide bases, and. provide an evolutionary snapshot of endonucleases at an early stage of divergence in their target specificity. (C) 2003 Elsevier Science Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据