Stereochemical Preferences Modulate Affinity and Selectivity among Five PDZ Domains that Bind CFTR: Comparative Structural and Sequence Analyses
Stereochemical Preferences Modulate Affinity and Selectivity among Five PDZ Domains that Bind CFTR: Comparative Structural and Sequence Analyses
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DOI：
10.1016/j.str.2013.09.019
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发表时间：
2014-01-07
期刊：
影响因子：
5.7
通讯作者：
Madden, Dean R.
中科院分区：
文献类型：
--
作者：
Amacher, Jeanine F.;Cushing, Patrick R.;Madden, Dean R.
PDZ结构域的相互作用涉及协调关键细胞过程的信号传导和运输途径。基于排列的PDZ结合基序识别沿着肽主链的某些位置的几个最有利的残基。然而，结合CAL （cftr相关配体）PDZ结构域的序列只显示了一个简并基序，这高估了高亲和相互作用体的真实数量。在这里，我们将扩展肽阵列基序分析与生化技术相结合，表明非基序“调节剂”残基影响CAL结合。13个CAL：肽复合物的晶体结构揭示了非基序位置的定义，但可容纳的立体化学环境，这反映在多序列取代阵列揭示的调制器偏好中。这些偏好有助于识别高亲和力的CAL结合序列，并对CAL和NHERF的PDZ结合产生不同的影响。因此，它们也有助于确定PDZ结构域网络的特异性，该网络调节顶端膜上CFTR的运输。
PDZ domain interactions are involved in signaling and trafficking pathways that coordinate crucial cellular processes. Alignment-based PDZ binding motifs identify the few most favorable residues at certain positions along the peptide backbone. However, sequences that bind the CAL (CFTR-associated ligand) PDZ domain reveal only a degenerate motif that overpredicts the true number of high-affinity interactors. Here, we combine extended peptide-array motif analysis with biochemical techniques to show that non-motif "modulator" residues influence CAL binding. The crystallographic structures of 13 CAL: peptide complexes reveal defined, but accommodating stereochemical environments at non-motif positions, which are reflected in modulator preferences uncovered by multisequence substitutional arrays. These preferences facilitate the identification of high-affinity CAL binding sequences and differentially affect CAL and NHERF PDZ binding. As a result, they also help determine the specificity of a PDZ domain network that regulates the trafficking of CFTR at the apical membrane.