Effects of Zn2+and Zn2+-coordinating glutamic acid residues on the superantigenic activities of staph-ylococcal enterotoxin C2
10.3760/cma.j.issn.0254-5101.2014.06.008
- VernacularTitle:Zn2＋及其谷氨酸结合位点突变对金黄色葡萄球菌肠毒素 C2超抗原活性的影响
- Author:
Yanli LIU
;
Rongcheng NIU
;
Mingkai XU
;
Xu LI
;
Jian SUN
;
Huiwen ZHANG
- Publication Type:Journal Article
- Keywords:
Zn2+;
Staphylococcal enterotoxin C2;
Superantigen;
T lymphocyte
- From:
Chinese Journal of Microbiology and Immunology
2014;(6):442-446
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the role of Zn 2+and Zn2+-coordinating glutamic acid residues ( 71Glu and 80Glu ) in the superantigenic activities of staphylococcal enterotoxin C2 ( SEC2 ) .Methods Over-lap PCR was used to amply genes encoding recombinant mutant proteins rSEC 2 ( E71A), rSEC2 (E80A) and rSEC2 (E71A/E80A).The mutant proteins were expressed in E.coli BL21 (DE3) and puri-fied by affinity chromatography .The differences of biological activities between rSEC 2 and its mutants were compared in vitro.The effects of Zn 2+on the superantigenic activities of rSEC 2 were evaluated by analyzing the proliferation of splenic lymphocytes in the presence or absence of ethylenediaminetetraacetic acid ( EDTA) .Results The substitution of glutamic acid residue at position 71 and 80 by alanine residue had no significant effects on the superantigenic activities and the conformational stability of rSEC 2 mutants.How-ever, traces of Zn2+(10μmol/L) could significantly enhance rSEC2-induced proliferation of splenic lympho-cytes, and only certain amount of Zn 2+could completely restore rSEC2-induced proliferation in the presence of EDTA.Conclusion This study indicated that mutations at Zn 2+-coordinating glutamic acid residues had no significant effects on the conformational stability and the superantigenic activities of SEC 2.Zn2+might play a role in regulating the superantigenic activities of SEC 2 through some indirect ways .
