Characterization of a thermostable manganese-containing superoxide dismutase from inshore hot spring thermophile Thermus sp.JM1  

作　　者：ZHU Yanbing LI Hebin ZHANG Xuqin ZHANG Chunyan XIANG Jionghua LIU Guangming 

机构地区：[1]School of Biotechnology Engineering, Jimei University, Xiamen 361021, China [2]Xiamen Medical College, Xiamen 361008, China

出　　处：《Acta Oceanologica Sinica》2011年第6期95-103,共9页海洋学报（英文版）

基　　金：The Natural Science Foundation of Fujian Province,China under contract Nos 2008J0067 and 2009J01033;the Program for New Century Excellent Talents in Fujian Province University under contract No.NCETFJ-2007;the Foundation for Innovative Research Team of Jimei University under contract No.2010A005

摘　　要：A thermostable superoxide dismutase （SOD） from the inshore thermophile Thermus sp. JM1 was purified to homogeneity by steps of fractional ammonium sulfate precipitation, DEAE-Sepharose chromatography and Phenyl-Sepharose chromatography. The specific activity of the purified native enzyme was 1 656 U/mg. A sod gene from this strain was cloned and overexpressed in Escherichia coli （E. coli）. The prepared apo-enzyme of the purified recombinant SOD （rSOD） was reconstituted with either Fe or Mn by means of incubation with appropriate metal salts. As a result, only Mn 2＋ - reconstituted rSOD （Mn-rSOD） exhibited the specific activity of 1 598 U/mg. SOD from Thermus sp. JM1 was Mn-SOD, judging by the specific activities analysis of Fe or Mn reconstituted rSODs and the insensitivity of the native SOD to both cyanide and H 2 O 2 . Both the native SOD and Mn- rSOD were determined to be homotetramers with monomeric molecular mass of 26 kDa and 27.5 kDa, respectively. They had high thermostability at 50 ° C and 60 ° C, and showed striking stability across a wide pH span from 4.0 to 11.0.A thermostable superoxide dismutase （SOD） from the inshore thermophile Thermus sp. JM1 was purified to homogeneity by steps of fractional ammonium sulfate precipitation, DEAE-Sepharose chromatography and Phenyl-Sepharose chromatography. The specific activity of the purified native enzyme was 1 656 U/mg. A sod gene from this strain was cloned and overexpressed in Escherichia coli （E. coli）. The prepared apo-enzyme of the purified recombinant SOD （rSOD） was reconstituted with either Fe or Mn by means of incubation with appropriate metal salts. As a result, only Mn 2＋ - reconstituted rSOD （Mn-rSOD） exhibited the specific activity of 1 598 U/mg. SOD from Thermus sp. JM1 was Mn-SOD, judging by the specific activities analysis of Fe or Mn reconstituted rSODs and the insensitivity of the native SOD to both cyanide and H 2 O 2 . Both the native SOD and Mn- rSOD were determined to be homotetramers with monomeric molecular mass of 26 kDa and 27.5 kDa, respectively. They had high thermostability at 50 ° C and 60 ° C, and showed striking stability across a wide pH span from 4.0 to 11.0.

关 键 词：manganese superoxide dismutase thermostability purification RECONSTITUTION 

分 类 号：Q939.03[生物学—微生物学] O614.711[理学—无机化学]