Evidence that the tightly bound magnesium in tubulin is associated with the N‐site GTP

FEBS Letters

Everett, Grover W.¹  Himes, Richard H.¹  Osei, Anthony A.¹ 

[1]Departments of Biochemistry and Chemistry, University of Kansas, Lawrence, KS 66045, USA

关键词: Tubulin;    Magnesium;    GTP;    GTP;    guanosine 5'-triphosphate;    GDP;    guanosine 5'-diphosphate;    GMPPCP;    guanylyl(β;    γ-methylene) diphosphonate;    GMPPNP;    guanylylimidodiphosphonate;    AP;    alkaline phosphatase;    Pipes;    piperazine-N;    N'-bis(2-ethanesulfonic acid);    EGTA;    ethylene glycol bis(β-aminoethyl ether)N;    N;    N';    N'-tetracetic acid;   

DOI  :  10.1016/0014-5793(90)80513-I

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In an attempt to determine whether the tightly bound Mg²⁺ found in purified tubulin in associated with the N-site GTP or the E-site GDP or GTP, we removed the E-site nucleotide by several means: (i) alkaline phosphatase treatment; (ii) displacement using excess GMPPCP; and (iii) polymerizing tubulin in the presence of alkaline phosphatase and non-hydrolyzable analogues. The Mg²⁺ content remained equal to about 1 tubulin under conditions where denaturation did not occur. Moreover, the Mg/GTP ratio always remained equal to 1. These results indicate that the Mg²⁺ is associated with the N-site GTP.

【 授权许可】

Unknown