Suoniemi A, Tanskanen J, Pentikäinen O, Johnson M S, Schulman A H
Institute of Biotechnology, University of Helsinki, Finland.
Mol Biol Evol. 1998 Sep;15(9):1135-44. doi: 10.1093/oxfordjournals.molbev.a026021.
Propagation of long terminal repeat (LTR)-bearing retrotransposons and retroviruses requires integrase (IN, EC 2.7.7.-), encoded by the retroelements themselves, which mediates the insertion of cDNA copies back into the genome. An active retrotransposon family, BARE-1, comprises approximately 7% of the barley (Hordeum vulgare subsp. vulgare) genome. We have generated models for the secondary and tertiary structure of BARE-1 IN and demonstrate their similarity to structures for human immunodeficiency virus 1 and avian sarcoma virus INs. The IN core domains were compared for 80 clones from 28 Hordeum accessions representative of the diversity of the genus. Based on the structural model, variations in the predicted, aligned translations from these clones would have minimal structural and functional effects on the encoded enzymes. This indicates that Hordeum retrotransposon IN has been under purifying selection to maintain a structure typical of retroviral INs. These represent the first such analyses for plant INs.
携带长末端重复序列（LTR）的逆转座子和逆转录病毒的传播需要由逆转元件自身编码的整合酶（IN，EC 2.7.7.-），该酶介导cDNA拷贝重新插入基因组。一个活跃的逆转座子家族BARE-1约占大麦（Hordeum vulgare subsp. vulgare）基因组的7%。我们构建了BARE-1整合酶的二级和三级结构模型，并证明它们与人类免疫缺陷病毒1和禽肉瘤病毒整合酶的结构相似。对代表大麦属多样性的28个大麦种质的80个克隆的整合酶核心结构域进行了比较。基于结构模型，这些克隆预测的比对翻译中的变异对所编码酶的结构和功能影响极小。这表明大麦逆转座子整合酶一直处于纯化选择之下，以维持逆转录病毒整合酶的典型结构。这些是对植物整合酶的首次此类分析。
