The crystal structure of TAL effector PthXo1 bound to its DNA target.
The crystal structure of TAL effector PthXo1 bound to its DNA target.
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DOI：
10.1126/science.1216211
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发表时间：
2012-02-10
期刊：
影响因子：
--
通讯作者：
Stoddard BL
中科院分区：
文献类型：
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作者：
Mak AN;Bradley P;Cernadas RA;Bogdanove AJ;Stoddard BL
TAL效应物的DNA识别由串联重复序列介导，每个串联重复序列的长度为33至35个残基，其通过独特的重复可变双残基（RVD）指定核苷酸。PthXo 1结合到其DNA靶标的晶体结构使用高通量计算结构预测确定，并通过重原子衍生化进行验证。每个重复序列形成一个左手的双螺旋束，向DNA呈现一个含RVD的环。这些重复序列自我结合形成一个右旋超螺旋，缠绕在DNA大沟周围。第一个RVD残基与蛋白质骨架形成稳定接触，而第二个残基与DNA有义链形成碱基特异性接触。两个简并的N-末端重复序列也与DNA相互作用。包含几个RVD和非典型协会，结构说明TAL效应DNA识别的基础。
DNA recognition by TAL effectors is mediated by tandem repeats, each 33 to 35 residues in length, that specify nucleotides via unique repeat variable diresidues (RVDs). The crystal structure of PthXo1 bound to its DNA target was determined using high-throughput computational structure prediction and validated by heavy-atom derivatization. Each repeat forms a left-handed, two-helix bundle that presents an RVD-containing loop to the DNA. The repeats self-associate to form a right-handed superhelix wrapped around the DNA major groove. The first RVD residue forms a stabilizing contact with the protein backbone, while the second makes a base-specific contact to the DNA sense strand. Two degenerate N-terminal repeats also interact with the DNA. Containing several RVDs and noncanonical associations, the structure illustrates the basis of TAL effector-DNA recognition.