In vivo and in vitro limited proteolysis of phaseolin: facts, suggestions and problems
2007
Rudakova, A. | Rudakov, S. | Lapteva, N. | Wilson, K. | Fukuda, T.
The latest experimental and theoretical results on the investigation of the in vitro and in vivo limited proteolysis of phaseolin are described and discussed. A part of the overall paradigm on limited proteolysis of phaseolin described in this paper is based on experimentally proved facts. These are: LP-(legumain) induced cleavage of the N220-T221 bond that in vitro is most susceptible; PP (papain like proteinase)-induced truncation of both subunit halves T1-N220 and T221-Y397, that generates the phaseolin-(LP+PP) structure; different susceptibility in vitro of the N220-T221 bond in alfa-type and beta-type subunits of phaseolin; the difference between limited proteolyses that occur in vivo in simultaneous presence of LP and PP, and in vitro under successive action of the same enzymes. Other parts of the paradigm are suggestions and speculations (cleavage points additional to those proved by N-terminal sequencing; explanations of peculiarity of limited and cooperative proteolyses of phaseolin compared to other 7S globulins, explanations for distinction between patterns of in vitro and in vivo limited proteolyses etc.). Moreover, the major question remains non-answered as to whether phaseolin-LP or phaseolin-(LP+PP) is the actual substrate for cooperative proteolysis carried out by PP. Nevertheless, we deem that the suggestions and even speculations combined in this paper together with univocal experimental results would be useful to encourage further investigations of phaseolin degradation.
显示更多 [+] 显示较少 [-]