抗辐射菌DNA结合蛋白的氨基酸序列分析

Analysis of Amino Acid Sequence of the DNA binding Proteins from Radioresistant Bacterium

目的 对抗辐射菌Ｄ．ｒａｄｉｏｕｄｕｒａｎｓ 的ＤＮＡ结合蛋白（ＤＢＰ） 进行Ｎ－ 末端氨基酸（ＡＡ） 序列分析，探讨其抗辐射分子学组成的特性。方法 采用地高辛（ＤＩＧ） 标记染色体ＤＮＡ 作为探针，ＳｏｕｔｈＷｅｓｔｅｒｎ 印迹法检测ＤＢＰ，在Ｎ－ 端ＡＡ 自动序列仪上分析ＡＡ序列。结果 野生型抗辐射菌存有８ 种ＤＢＰ的特性蛋白（分子量分别为１２２、９３、３３、２９、１６、１５、１４ 和１２ｋｄ）；ＡＡ 序列分析发现其中９３ｋｄ 和３３ｋｄ 可能为新的蛋白质；两种新ＤＢＰ 的表达水平随不同培养基和培养时间而变化。结论 抗辐射菌的ＤＢＰ，尤其是９３ｋｄ 和３３ｋｄ

Objective Analysis was carried out on the N terminal amino acid (AA) sequence in DNA binding proteins (DBPs) from a radioresistant bacterium, i.e. Deinococcus radiodurans (D.radiodurans) ,for purposes of exploring their radioresistant characteristics of molecular components.Methods The DBPs from three radioresistant bacteria were determined by South Western bloting using the chromosomal DNA labeled with Digoxin (DIG) as a probe.The N terminal AA sequence in some DBPs was analysed by a AA autosequencer.Results There were eight DPBs in three wild type of D.radfodurans ,and their molecular weights were 122、93、33、29、16、15、14 and 12kd respectively.The DBPs of 93 and 33 kd from wild type of KR1 might be two novel proteins according to results of the AA sequence analysis.The expression level of the two DBPs changed with different culture media and culturing time.Conclusion The DPBs from radioresistant bacterium,especially the DBPs of 93 and 33 kd, were closely related to the radioresistance of D.radiodurans.