Clement J M, Charbit A, Martineau P, O'Callaghan D, Szmelcman S, Leclerc C, Hofnung M
Unité de Programmation Moléculaire et Toxicologie Génétique (CNRS URA 271), Institut Pasteur, Paris.
Ann Biol Clin (Paris). 1991;49(4):249-54.
The construction of recombinant proteins by genetic engineering has opened new avenues in basic research (studies on protein organization, protein folding, immunogenicity of proteins, ...) and many different applications. Recombinant proteins which keep properties of both parental proteins are especially interesting. For example, if one protein--the vector protein--is targeted to a given cellular compartment, the other protein--the passenger--may be identically targeted. Also, if the vector protein can be purified by a simple affinity chromatographic procedure, this property may be extended to the passenger. The authors have developed a genetic procedure to detect "permissive" sites within potential vector proteins so that genetic fusion to these sites keep most or all biological properties of the vector. When they used LamB, an outer membrane protein from E. coli, foreign sequences could be expressed at the bacterial cell surface. This may lead to several types of applications: live bacterial vaccines, simple diagnostic tests, selection procedures for peptides with biological activity. When they used the MalE protein, a periplasmic maltose binding protein from E. coli, the passengers could be exported and purified in one-step high affinity chromatography in mild non-denaturing conditions. This led us to a simple preparation and purification scheme for the soluble part of the CD4 receptor for the Human Immunodeficiency Virus (HIV).
通过基因工程构建重组蛋白为基础研究（关于蛋白质结构、蛋白质折叠、蛋白质免疫原性等的研究）及许多不同应用开辟了新途径。兼具双亲蛋白质特性的重组蛋白尤其令人感兴趣。例如，如果一种蛋白质（载体蛋白）定位于特定的细胞区室，那么另一种蛋白质（乘客蛋白）可能也会同样定位于此。此外，如果载体蛋白能够通过简单的亲和层析程序进行纯化，那么这一特性可能会延伸至乘客蛋白。作者们开发了一种基因程序来检测潜在载体蛋白中的“允许”位点，以便与这些位点进行基因融合时能保留载体的大部分或全部生物学特性。当他们使用大肠杆菌的外膜蛋白LamB时，外源序列能够在细菌细胞表面表达。这可能会带来多种应用：活细菌疫苗、简单诊断测试、具有生物活性的肽的筛选程序。当他们使用大肠杆菌的周质麦芽糖结合蛋白MalE时，乘客蛋白能够在温和的非变性条件下通过一步高亲和层析进行输出和纯化。这为人类免疫缺陷病毒（HIV）的CD4受体可溶性部分带来了一种简单的制备和纯化方案。
