MERCURY TRANSPORT PROTEINS OF BACTERIAL MERCURY DETOXIFICATION SYSTEM

展示在丝状体上的肽的结构 噬菌体病毒颗粒可以作为表位进行研究， 蛋白质的独立折叠单位。 肽的功能与激素相同 或其它类型的效应物，当它们结合可溶性或膜结合时 受体。 当它们与抗体结合时，它们也充当表位。 肽序列基本上有两种来源。 肽可以 选自可通过生物学方法制备的文库， 特别是噬菌体展示，或通过多种合成策略。 文库的目的是产生所有可能的肽 然后，根据所选的一个或几个感兴趣的 它们对靶分子如抗体的结合亲和力， 受体蛋白 外壳蛋白的N-末端区域提供 有利于稳定肽构象的环境，如图所示 通过增加插入的氨基酸序列的生物活性， 与游离肽相比。 固态NMR 噬菌体上展示的几个表位的光谱给出了直接的 肽的结构折叠的证据。 15 n化学位移 酰胺的各向异性（CSA）和15 N-1H偶极耦合测量 这些肽的骨架位点表明这些肽是 固定在病毒颗粒上，并提供 他们的折叠。 来自主要抗原的12个残基肽的表位 人类疟疾孢子的决定子被发现折叠成 三圈。 发现HIV-1 V3环的6个残基表位是 在噬菌体颗粒上是移动的。 HIV-1抗体与此的结合 展示在噬菌体上的表位导致固定的折叠结构。

The structure of peptides displayed on the filamentous bacteriophage virus particles can be studied as epitopes and independent folding units of proteins. Peptides function as hormones or other types of effectors when they bind soluble or membrane bound receptors. They also act as epitopes when they bind to antibodies. There are basically two sources of peptide sequences. Peptides can be selected from libraries, which can be prepared by biological methods, in particular phage display , or by a variety of synthetic strategies. The purpose of the library is to generate all of the possible peptides of interest, and then to select the one or few of interest based on their binding affinity for a target molecule such as an antibody or receptor protein. The N-terminal region of the coat protein provides an environment conducive to stabilizing peptide conformation, as shown by the increased biological activity of amino acid sequences inserted into the coat protein versus the free peptide. Solid-state NMR spectra of several epitopes displayed on the phage gave direct evidence of the structural fold of the peptides. 15N chemical shift anisotropy (CSA) and 15N-1H dipolar coupling measurements of the amide backbone sites of these peptides indicate that the peptides are immobilized on the virus particle and provide structural details of their fold. Epitopes of a 12 residue peptide from the main antigenic determinant of the human malaria sporozite were found to fold into three turns. The 6 residue epitope of HIV-1 V3 loop was found to be mobile on the phage particle. Binding of an HIV-1 antibody to this epitope displayed on phage resulted in an immobile folded structure.