Domain swapping in allosteric modulation of DNA specificity.
Domain swapping in allosteric modulation of DNA specificity.
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DOI：
10.1371/journal.pbio.1000554
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发表时间：
2010-12-07
期刊：
影响因子：
9.8
通讯作者：
Horton NC
中科院分区：
文献类型：
--
作者：
Park CK;Joshi HK;Agrawal A;Ghare MI;Little EJ;Dunten PW;Bitinaite J;Horton NC
The structure of two DNA-bound SgrAI enzyme dimers is presented, along with mutagenesis experiments supporting a role for this structure in polymer formation and the activation of DNA cleavage by SgrAI. SgrAI is a type IIF restriction endonuclease that cuts an unusually long recognition sequence and exhibits allosteric self-modulation of cleavage activity and sequence specificity. Previous studies have shown that DNA bound dimers of SgrAI oligomerize into an activated form with higher DNA cleavage rates, although previously determined crystal structures of SgrAI bound to DNA show only the DNA bound dimer. A new crystal structure of the type II restriction endonuclease SgrAI bound to DNA and Ca2+ is now presented, which shows the close association of two DNA bound SgrAI dimers. This tetrameric form is unlike those of the homologous enzymes Cfr10I and NgoMIV and is formed by the swapping of the amino-terminal 24 amino acid residues. Two mutations predicted to destabilize the swapped form of SgrAI, P27W and P27G, have been made and shown to eliminate both the oligomerization of the DNA bound SgrAI dimers as well as the allosteric stimulation of DNA cleavage by SgrAI. A mechanism involving domain swapping is proposed to explain the unusual allosteric properties of SgrAI via association of the domain swapped tetramer of SgrAI bound to DNA into higher order oligomers. Restriction endonucleases protect their bacterial hosts from viral infection by cleaving any invading viral DNA. One such enzyme, SgrAI, cleaves DNA very slowly but can be activated to cleave DNA 200 times more rapidly. Activation occurs when the enzyme interacts with two or more copies of DNA containing its recognition sequence. We have recently discovered that this enzyme forms polymers when activated. Polymerization may function to sequester the activated enzyme away from, and thereby protect, the host DNA. We have determined the three-dimensional structure of two SgrAI enzymes, each bound to their recognition sequence, interacting in a way that may occur in the polymer. The observed interaction involves a very unusual swapping of parts of each enzyme, termed domain swapping, which has rarely been found in enzyme activation. In support of the idea that this interaction operates during polymer formation and activation of SgrAI, we have shown that mutations designed to interfere with the interaction eliminate both activation and polymerization of the enzyme.
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DOI：
10.1038/79032
发表时间：
2000-09-01
期刊：
NATURE STRUCTURAL BIOLOGY
影响因子：
--
作者：
Deibert, M;Grazulis, S;Huber, R
通讯作者：
Huber, R
影响因子：
5.6
作者：
Embleton, ML;Vologodskii, AV;Halford, SE
通讯作者：
Halford, SE
DOI：
10.1107/s0907444998003254
发表时间：
1998-09-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
--
作者：
Brunger, AT;Adams, PD;Warren, GL
通讯作者：
Warren, GL
影响因子：
14.9
作者：
Dunten PW;Little EJ;Gregory MT;Manohar VM;Dalton M;Hough D;Bitinaite J;Horton NC
通讯作者：
Horton NC
DOI：
10.1107/s0907444902016657
发表时间：
2002-11-01
影响因子：
2.2
作者：
Adams, PD;Grosse-Kunstleve, RW;Terwilliger, TC
通讯作者：
Terwilliger, TC