Institute for Structural and Medicinal Biochemistry, center for Medical Biotechnology-ZMB, Faculty of Biology and Geography, University of Duisburg-Essen, 45141, Essen, Germany.
J Pept Sci. 2013 Jun;19(6):362-9. doi: 10.1002/psc.2510. Epub 2013 Apr 18.
Peptidyl-prolyl cis-trans isomerases (PPIases) are the enzymes that increase the rate of isomerization of the peptide bond N-terminal to the proline substrate. Par14 and its isoform Par17 belong to the Parvulin family of PPIases. Par14 can bind AT-rich double-stranded DNA and was shown to be part of the pre-ribosomal ribonucleoprotein (pre-rRNP) complexes, where it functions as an RNA processing factor that is involved in ribosome biogenesis. Its longer isoform Par17 is expressed only in cells of hominids, where it is targeted to the mitochondria. To find binding partners (peptides or proteins) for Par17, we applied the phage display technology. We panned 7-mer and 12-mer peptide libraries against Par17. The consensus sequence XHSXVHØ, where X can be any amino acid and Ø is a hydrophobic amino acid, was enriched from both libraries. We demonstrate the binding of this motif to the PPIase domain of Par17 using phage ELISA and NMR spectroscopy. We propose that residues Met90, Val91, Phe94, Gln95, Glu96, and Ala98 of Par17 are involved in substrate recognition, and that the phage display-selected motif XHSXVHØ can be recognized by Par17 PPIase domain in vivo.
肽基脯氨酰顺反异构酶（PPIases）是能够增加脯氨酸底物 N 端肽键异构化速度的酶。Par14 和其同工型 Par17 属于 Parvulin 家族的 PPIases。Par14 可以结合富含 AT 的双链 DNA，并被证明是核糖体前体核糖核蛋白（pre-rRNP）复合物的一部分，在那里它作为一种 RNA 加工因子参与核糖体生物发生。它的较长同工型 Par17 仅在同源生物的细胞中表达，在那里它被靶向到线粒体。为了寻找 Par17 的结合伴侣（肽或蛋白质），我们应用了噬菌体展示技术。我们针对 Par17 筛选了 7 肽和 12 肽文库。从两个文库中都富集到了 XHSXVHØ 这个共有序列，其中 X 可以是任何氨基酸，Ø 是一个疏水性氨基酸。我们使用噬菌体 ELISA 和 NMR 光谱学证明了该模体与 Par17 的 PPIase 结构域的结合。我们提出 Par17 的 Met90、Val91、Phe94、Gln95、Glu96 和 Ala98 残基参与底物识别，并且噬菌体展示选择的 motif XHSXVHØ 可以在体内被 Par17 PPIase 结构域识别。
