应用荧光光谱法研究植物LEA3蛋白11-氨基酸基序的保护功能

Application of Fluorescence Spectroscopy in Studying the Protective Function of 11-Amino Acid Motif of Group3 Late Embryogenesis Abundant Protein

胚胎晚期富集蛋白(late embryogenesis abundant,LEA)是增强生物抵抗干旱、低温和盐渍等多种胁迫的重要功能蛋白,但其保护机理仍不清楚。本文利用紫外光谱法证实,含多拷贝11-氨基酸基序的多肽(如PM2D和PM2E)可较好的保护经冻融的乳酸脱氢酶(LDH)活性。进一步通过荧光光谱法证实,含多拷贝11-氨基酸基序的多肽可通过多位点协同结合模式,稳定LDH酶的结构。而含低拷贝11-氨基酸基序的多肽(如PM2F和PM2G)与LDH酶只有一种结合位点,二者的结合强度较弱,因而不能表现出对LDH酶活性的保护作用。此外,含多拷贝11-氨基酸的多肽与海藻糖在保护LDH酶活性上存在协同作用,且二者有着不同的保护机理。

Late embryogenesis abundant protein（LEA） can enhance the tolerance of organisms under drought,low-temperature and other stress conditions.However,their protection mechanisms are still unclear.In the present paper,the peptides consisting of multi-copies of 11-amino acid motif,such as PM2D and PM2E are proved to protect the activity of the lactate dehydrogenase（LDH） from freeze-thaw by using ultroviolet spectrometry.Furthermore,the fluorescence spectroscopic results show that the peptide consisting of multi-copies of 11-amino acid can stabilize the structure of LDH through synergy and multi-sites binding.However,the peptides consisting of less copies of 11-amino acid,such as PM2F and PM2G bind to LDH through one site,and the binding is weak.They thus can not protect the activity of LDH.In addition,the peptides consisted of multi-copies of 11-amino acid protect LDH by acting with trehalose synergically,and the protection mechanisms of LEA and trehalose on LDH are different.