Department of Biology, Texas A&M University, College Station, TX 77843, USA.
J Mol Biol. 2012 Mar 2;416(4):518-33. doi: 10.1016/j.jmb.2011.12.064. Epub 2012 Jan 5.
The fungal arginine attenuator peptide (AAP) is a regulatory peptide that controls ribosome function. As a nascent peptide within the ribosome exit tunnel, it acts to stall ribosomes in response to arginine (Arg). We used three approaches to probe the molecular basis for stalling. First, PEGylation assays revealed that the AAP did not undergo overall compaction in the tunnel in response to Arg. Second, site-specific photocross-linking showed that Arg altered the conformation of the wild-type AAP, but not of nonfunctional mutants, with respect to the tunnel. Third, using time-resolved spectral measurements with a fluorescent probe placed in the nascent AAP, we detected sequence-specific changes in the disposition of the AAP near the peptidyltransferase center in response to Arg. These data provide evidence that an Arg-induced change in AAP conformation and/or environment in the ribosome tunnel is important for stalling.
真菌精氨酸衰减肽（AAP）是一种调节肽，可控制核糖体功能。作为核糖体出口隧道中的新生肽，它可以响应精氨酸（Arg）来阻止核糖体。我们使用三种方法来探究其阻止的分子基础。首先，PEGylation 测定表明，Arg 并未导致 AAP 在隧道中整体变紧凑。其次，定点光交联显示，Arg 改变了野生型 AAP 的构象，但对非功能突变体则没有，相对于隧道而言。第三，使用荧光探针的时间分辨光谱测量，我们检测到在响应 Arg 时，在肽基转移酶中心附近，AAP 的排列方式发生了序列特异性变化。这些数据表明，Arg 诱导的 AAP 构象和/或核糖体隧道环境变化对于阻止是很重要的。
