Nanomolar Binding of Peptides Containing Noncanonical Amino Acids by a Synthetic Receptor
Nanomolar Binding of Peptides Containing Noncanonical Amino Acids by a Synthetic Receptor
复制标题
DOI：
10.1021/ja207825y
复制
发表时间：
2011-10-26
影响因子：
15
通讯作者：
Urbach, Adam R.
中科院分区：
文献类型：
--
作者：
Logsdon, Leigh A.;Schardon, Christopher L.;Urbach, Adam R.
本文报道了人工合成的受体瓜环（Q7）对苯丙氨酸衍生物及其多肽的分子识别。苯丙氨酸的4-叔丁基和4-氨基-甲基衍生物（tBuPhe和AMPhe）从筛选中鉴定为对Q7具有比苯丙氨酸高20-30倍的亲和力。将这些残基放置在模型三肽（X-Gly-Gly）的N-末端，导致对tBuPhe-Gly-Gly的亲和力没有变化，但对AMPhe-Gly-Gly的亲和力显著增加500倍，其在中性磷酸盐缓冲液中以0.95 nM的平衡解离常数（K-d）值结合Q7。结构-活性研究表明，三个官能团以积极合作的方式工作，以实现这种非凡的稳定性（1）N-末端铵基团，（2）侧链铵基团，和（3）肽骨架。将氨甲基基团添加到Phe中显著提高了肽与氨基酸的选择性以及N-末端与非末端位置的选择性。重要的是，Q7与N-末端AMPhe的结合比任何典型氨基酸残基更紧密几个数量级。该系统的高亲和性、单位点选择性和小修饰使其对开发最小亲和标签具有吸引力。
This paper describes the molecular recognition of phenylalanine derivatives and their peptides by the synthetic receptor cucurbit[7]uril (Q7). The 4-tert-butyl and 4-amino-methyl derivatives of phenylalanine (tBuPhe and AMPhe) were identified from a screen to have 20-30-fold higher affinity than phenylalanine for Q7. Placement of these residues at the N-terminus of model tripeptides (X-Gly-Gly), resulted in no change in affinity for tBuPhe-Gly-Gly, but a remarkable 500-fold increase in affinity for AMPhe-Gly-Gly, which bound to Q7 with an equilibrium dissociation constant (K-d) value of 0.95 nM in neutral phosphate buffer. Structure-activity studies revealed that three functional groups work in a positively cooperative manner to achieve this extraordinary stability (1) the N-terminal ammonium group, (2) the side chain ammonium group, and (3) the peptide backbone. Addition of the aminomethyl group to Phe substantially improved the selectivity for peptide versus amino acid and for an N-terminal vs nonterminal position. Importantly, Q7 binds to N-terminal AMPhe several orders of magnitude more tightly than any of the canonical amino acid residues. The high affinity, single-site selectivity, and small modification in this system make it attractive for the development of minimal affinity tags.