The Gag proteins of retroviruses play an essential role in virus particle assembly by forming a protein shell or capsid and thus generating the virion compartment. A variety of human proteins have now been identified with structural similarity to one or more of the major Gag domains. These human proteins are thought to have been evolved or “domesticated” from ancient integrations due to retroviral infections or retrotransposons. Here, we report that X-ray crystal structures of stably folded domains of MOAP1 (modulator of apoptosis 1) and PEG10 (paternally expressed gene 10) are highly similar to the C-terminal capsid (CA) domains of cognate Gag proteins. The structures confirm classification of MOAP1 and PEG10 as domesticated Gags, and suggest that these proteins may have preserved some of the key interactions that facilitated assembly of their ancestral Gags into capsids.

中文翻译：

---

MOAP1 和 PEG10 源自逆转录病毒/逆转录转座子 Gag 蛋白的结构证据

逆转录病毒的 Gag 蛋白通过形成蛋白质外壳或衣壳，从而产生病毒粒子隔室，在病毒颗粒组装中发挥重要作用。现在已经鉴定出与一个或多个主要 Gag 结构域具有结构相似性的多种人类蛋白质。由于逆转录病毒感染或逆转录转座子，这些人类蛋白质被认为是从古代整合进化而来或“驯化”的。在这里，我们报告了 MOAP1（细胞凋亡调节剂 1）和 PEG10（父本表达基因 10）的稳定折叠域的 X 射线晶体结构与同源 Gag 蛋白的 C 端衣壳 (CA) 域高度相似。这些结构确认 MOAP1 和 PEG10 被归类为驯化的 Gags，