【讨论】研究分子伴侣和伙伴基因的方法和思路

再来一个话题，如果要研究一个已知分子的分子伴侣或者伙伴基因，除了较为常用的酵母双杂交和免疫共沉淀，还有什么其他的办法，希望大家提供一点思路。
此外请教一下分子伴侣（molecular chaperone）和伙伴基因（partner molecular or gene）是一个概念吗？如果不是有什么区别吗？
多谢！

分子伴侣是细胞中一大类蛋白质, 是由不相关的蛋白质组成的一个家系，它们介导其它蛋白质的正确装配，但自己不成为最后功能结构中的组分。分子伴侣的概念有三个特点:
①凡具有这种功能的蛋白, 都称为分子伴侣, 尽管是完全不同的蛋白质;
②作用机理是不清楚的,故用了“介导”二字,以含糊其辞,“帮助”二字可理解为: 通过催化的或非催化的方式, 加速或减缓组装的过程, 传递组装所需要的空间信息, 也可能抑制组装过程中不正确的副反应。
③分子伴侣一定不是最终组装完成的结构的组成部分, 但不一定是一个分离的实体。如一些蛋白水解酶的前序列, 以及一些核糖核蛋白体的加工前的部分, 若具分子伴侣的作用, 也称为分子伴侣。组装的涵意比较广,主要指:帮助新生肽的折叠、帮助新生肽成熟为活性蛋白、帮助蛋白质跨膜定位、亚基组装等。
伙伴基因一般是指融合蛋白。可以参考：http://d.wanfangdata.com.cn/Periodical_gwyx-sxjxyxfc200701019.aspx获得更多信息。

多谢版主解答，分子伴侣分析的很透彻，但是伙伴基因就是指融合蛋白吗？
还有研究方法是不是都是差不多的，都是CO-IP方法？

SUMO fusion technology for enhanced protein production in prokaryotic and eukaryotic expression systems.
Panavas T, Sanders C, Butt TR.

Life Sensors Inc., Malvern, PA, USA.

In eukaryotic cells, the reversible attachment of small ubiquitin-like modifier (SUMO) protein is a post-translational modification that has been demonstrated to play an important role in various cellular processes. Moreover, it has been found that SUMO as an N-terminal fusion partner enhances functional protein production in prokaryotic and eukaryotic expression systems, based upon significantly improved protein stability and solubility. Following the expression and purification of the fusion protein, the SUMO-tag can be cleaved by specific (SUMO) proteases via their endopeptidase activity in vitro to generate the desired N-terminus of the released protein partner. In addition to its physiological relevance in eukaryotes, SUMO can, thus, be used as a powerful biotechnological tool for protein expression in prokaryotic and eukaryotic cell systems.In this chapter, we will describe the construction of a fusion protein with the SUMO-tag, its expression in Escherichia coli, and its purification followed by the removal of the SUMO-tag by a SUMO-specific protease in vitro.

再给一个例子看看。

我凑凑热闹。两个概念肯定不同。但是，也不能等同融合蛋白吧。融合是手段，不是目的。

我没有看文献本身，但是，我理解，partner应该指一个跟分子伴侣一起起作用的分子，上面的例子是SUMO,下面的例子是cochaperone.

Mol Microbiol. 2007 Nov;66(4):840-57. Epub 2007 Oct 4.

The Hsp70 chaperone machines of Escherichia coli: a paradigm for the repartition of chaperone functions.
Genevaux P, Georgopoulos C, Kelley WL.

Laboratoire de Microbiologie et Génétique Moléculaire, IBCG, CNRS Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse, Cedex 09, France. pierre.genevaux@ibcg.biotoul.fr

Molecular chaperones are highly conserved in all free-living organisms. There are many types of chaperones, and most are conveniently grouped into families. Genome sequencing has revealed that many organisms contain multiple members of both the DnaK (Hsp70) family and their partner J-domain protein (JDP) cochaperone, belonging to the DnaJ (Hsp40) family. Escherichia coli K-12 encodes three Hsp70 genes and six JDP genes. The coexistence of these chaperones in the same cytosol suggests that certain chaperone-cochaperone interactions are permitted, and that chaperone tasks and their regulation have become specialized over the course of evolution. Extensive genetic and biochemical analyses have greatly expanded knowledge of chaperone tasking in this organism. In particular, recent advances in structure determination have led to significant insights of the underlying complexities and functional elegance of the Hsp70 chaperone machine.

是的，我也觉得伙伴分子和融合蛋白是两把事，融合蛋白一般是指人工合成，或者一些肿瘤中产生的融合基因的产物。
对于伙伴基因我的理解是，同时发挥类似的作用的两个或多个分子，但是我觉得这个概念太宽泛了，呵呵。